Category: Environment

Post #2085: The mess that is the ice-melt market, in one phrase: Pet-safer.

 

I am still trying to get up to speed on ice-melting compounds.  So far, two things appear crystal clear.

First, rock salt — sodium chloride, NaCl, halite — is the worst ice-melting compound, in terms of metal and concrete damage, environmental harm, and pet safety.

Second, most of the claims, made by most ice melters, are, at best, exaggerations.

Pet-safer:  Crossing the line on exaggerated product claims.

But some ice-melter claims — particularly regarding “pet-safe” and “eco-friendly” — are purposefully deceptive.

And, oddly enough, those purposefully-deceptive claims of “pet-safe” and “eco-friendly” ice melts work exactly the same way.  In order to be legal, they only claim to be pet-safer or eco-friendlier.  Than what, you might ask?  Than pure rock salt.  So the first takeaway is that anything that’s even trivially better than pure rock salt — such as rock salt with some tiny amount of additives — can advertise itself as both “pet-safer” and “eco-friendlier” (…. than rock salt).

Surely we agree that rock salt is not pet safe?

By way of making this as clear as possible, let me narrow it to dogs.  And focus on the bottom of the barrel — rock salt.

A dog will get sick if it ingests too much (table, NaCl) salt.  One reference listed a dog-lethal dose of sodium chloride (salt) as 4 grams per kilogram body weight (Source:  Veterinary Toxicology, 4th Edition.)  Thus a 30-pound dog that manages to eat two ounces of rock salt, and keep it down, might reasonably die from doing that.  (That’s about three level tablespoons of table salt.)

And a dog could pretty clearly get sick from a lower dose than that.  Salt poisoning leads to vomiting, diarrhea, and, if it proceeds far enough, to neurological symptoms (e.g., inability to walk).

Salt poisoning of dogs does not appear to be very common.  Another reference said that in 1998, there were just 50 such cases reported to ASPCA poison control hot line.  Currently, salt poisoning doesn’t make the top 10 list of common pet poisons.

And, from reading a few case reports, ice-melt poisoning can occur if a dog takes a big gulp of the stuff, straight out of the bag.  But, in general, that’s not the problem being addressed by use of “pet-safe” de-icers.  A mouthful of de-icer is going to be bad for your pet, no matter what.

Instead, people who buy pet-safe ice melt are worried about dogs walking on areas treated with (e.g.) rock salt as an ice-melter.  First, salt irritates dogs’ paws.  And second, dogs ingest salt from licking off salt crystals stuck on or in their paws,

The upshot of all that is that rock salt (NaCl) is something you don’t want to see in a “pet-safe” ice melt.

So what do I find, off the crack of the bat, on the Home Depot website?

And that’s not a one-off accident.  Here’s the same nonsense from Uline, a supplier of industrial products of all types:

So …

Once you move beyond colored rock salt — clearly not pet-safe — there’s some real ambiguity as to what’s safe or not.

Urea is typically considered fully safe for dogs and cats (but is not safe for ruminants).  But urea is basically high-potency nitrogen fertilizer.

I can’t see myself dumping a 50-pound bag of 43-0-0 fertilizer on the driveway in winter.  Or in any season, really.

Plus, it’s a poor ice melter, and you’d be hard-pressed to find it bagged in bulk for consumer ice-melt use.  Apparently, it is only commonly used in specialty situations such as elevated metal walkways, where lack of metal corrosion is the key concern for the ice-melt.

Acetate ice melters (calcium magnesium acetate (CMA) and potassium acetate (KAC)) are considered pet-safe by some.  But these, too, perform relatively poorly as ice-melters, and are expensive per effective melting dose, as well.  They have the additional advantage of not being chloride salts, and so being less toxic to the aquatic environment than (say) rock salt.

Beware “with CMA”, just as you should beware pet friendlier.  A lot of ice-melt blends want to bask in the glow of CMA without the bother and expense of actually including much of it in their blend.   (Plus, the ice melter probably works better as an ice melter if you go light on the CMA, because CMA apparently is not a very good ice melter.  It just has the big advantage of killing less stuff than chloride salts do.)

Magnesium chloride is considered safer for pets than other chloride salts.  It is sold, for example, by both PetSmart and PetCo as a pet-safer de-icer.  It also performs quite well as a de-icer.  From a pet-safety standpoint, the only drawback appears to be price.  In retail packaging, MgCl2 appears to cost anywhere from five to ten times as much as rock salt.  But, as a chloride salt, this is not materially better than rock salt, from the standpoint of toxicity to the aquatic environment.  And some references suggest that it causes more damage to concrete than rock salt does, particular to newer (under-one-year-old) concrete.

Conclusion

I have no dog in this fight, if you will excuse the phrase.  I don’t own a pet, so this isn’t my problem.  I only stumbled across it in looking for ice melts that aren’t chloride salts, hoping for lower environmental impact.  And was vaguely outraged once I figured the whole pet-friendlier thing as discussed above.

But I note that it is a common and accepted practice in the ice-melt market to take a bag of common rock salt, color it (green or blue, inevitably), sprinkle in some actually pet-safe materials, slap “pet-safer” on the bag, and then double the amount charged for it. 

Unlike pet food, nobody appears to regulate anything about “pet-safer” de-icers.  Even though the danger arises from pets eating the stuff.  Contrast that the the multi-agency Federal regulation of pet food.  (Not that the Feds need to regulate de-icers per se, but the use of “pet-safer” and similar legal-but-misleading claims.)

Unsurprisingly, then, a lot of stuff offered in the big-box hardware stores as “pet-safer” ice melt is just rock salt (plus a tiny amount of additives) sold at a steep markup.

Caveat emptor.

Post #2084: Homeopathic pavement treatment.

 

I’m no longer going to use pavement de-icer (rock salt, road salt, ice melt).

For now, at least.

That’s because, upon inspection, much about the modern road salt/pavement de-icer market confuses me.

But in my defense, I had a lot of help, getting confused.  The whole retail “de-icer” market pings my bullshit detector in some strong and unpleasant ways.  Not just the simple stuff (“melts as low as … ).  More importantly, “pet-safe” and “eco-friendly” have quietly morphed into their mealy-mouthed “safer” and “friendlier” versions.  And not in a good way.

Road salt is a deep topic, but I have to start somewhere.

As described in Section 1 below, I did not intend to fuse the principles of homeopathy with those of winter pavement maintenance.  That happened entirely as a result of my own stupidity.

But, per Section 2 (next post), I had a lot of help being stupid about it.  Pavement de-icers are arguably the worst consumer product I’ve ever seen, in terms of manufacturers’ claims and deliberately misleading marketing.

Plus, Section 3, the practical use of chemical pavement de-icer is complicated. Even absent all the baloney presented by sellers of de-icers, there’s a lot to unpack.  I’m not sure I understand the chemistry part of it, yet, let alone the weather’s contribution.

And, Section 4, most (perhaps all) commonly-used de-icers are crap for the environment, especially the aquatic environment.  I can’t complain about the taste of road salt in the drinking water if I’m spreading this stuff on my own driveway.

This is just the first of several posts on pavement de-icer.

Part 1:  Driveway homeopathy

1A:  The hasty but satisfying post-hoc conclusion

Source:  Good ol’ clipart-library.com, which has upped its game with an on-the-fly AI picture generator.

A few days ago, I salted my driveway, using calcium chloride pellets.  The idea was that the (calcium chloride) salt would melt a coming light snow, causing it to run off my driveway as (slightly salty) water, and, ideally, leaving me with bare pavement. Instead of a driveway with an inch of snow on it.  This, as being preferable to re-shoveling my driveway to remove a light coating of snow.  And this to be achieved despite temperatures consistently (but not hugely) below 32F.

By the end of the next day, my driveway was dry and snow/ice free.

So the salt obviously worked, right?  End-of-story.

Part 2:  But … science

As I was patting myself on the back, I could not help but notice that all my neighbors’ driveways were also dry and snow-free.

Which, after a moment’s solemn reflection, pretty strongly suggested that my salting my driveway was a complete waste of time.

I’m pretty sure none of my neighbors salted theirs.

Part 3:  thus was born the short-lived science of driveway homeopathy.

First, I found a pretty chart.  (This is, in fact, an excellent chart from an excellent practical reference.)

Source:  National Tank Outlet.  These folks sell the tanks you need to store this stuff at industrial scale.

Those substances are all salts, chemically speaking:

  • CaCl2 — calcium chloride
  • NaCl — salt– rock salt — halite — sodium chloride
  • MgCL2 — magnesium chloride
  • CMA — calcium magnesium acetate ( calcium acetate and magnesium acetate).
  • KAC — potassium acetate.

Then doing this crude calculation:

And then, only as a last resort, actually reading the directions on the bag.  Which, they just flat out say, per for 1000 square feet, for some “typical” conditions (I guess), I should use just touch more than what I calculated above.

The upshot is that I should use at least an entire 50-pound bag of calcium chloride.  On a 1000-square-foot section of driveway.  That, to get rid of an (one) inch of typical snowfall.  That should make a brine strong enough to have all that snow turn to water and run off, even though the weather is (maybe) 10 degrees below freezing.  This, instead of shoveling the driveway, again, for the new inch of snow that fell.

I’ve never used it at anything close to that rate.  I use it a few pounds at a time.  (And, correspondingly, my first (and current) bag of calcium chloride is at least a decade old.)  Nor will I ever.

Ergo, I have been engaging in homeopathic ice melting.  Sure, I start off with strong brine, when those first few snowflakes hit those salt (calcium chloride) crystals (pellets).  Implicitly, I must have believed that after adding a whole lot more water (in the form of an inch of snow), the resulting very dilute brine would somehow recall the strength it once had, and so continue to melt the snow.

Contrary to the laws of physics and chemistry.  Or common sense.

Or the directions on the bag.

Or all of the above.

Conclusion

For now, the simple message is that homeopathic pavement de-icer helps no-one.  Avoid it.

It achieves nothing while causing slight environmental harm. It’s a net negative, except perhaps in (easily deceived) the mind of the user.

So, with regard to salting the pavement:  Do.  Or do not.

Crazily enough, I have a lot more to say about ice melters.  That’ll come out in the next posts.

Post #2083: Cold wave, heat pump, wood stove secondary heating.

 

Sometimes, all you need is a warm place.

Cold wave:  It’s going to get cold next week.

How cold?

In Vienna, VA, the National Weather Service is predicting a nighttime low of 4F, a week from now.

That’s rare but not totally unexpected.   

As of 1990, Vienna was at the edge of USDA plant hardiness Zone 6B, and could expected to see (and did see) occasional wintertime lows down to minus 5F

Three decades later, and we’re ten degrees warmer.  (In terms of our expected extreme low winter temperature).  As of the most recent USDA Hardiness Zone map, Vienna has moved into Zone 7B, with an expected extreme low of 5F.

That trend came through clearly in my analysis of annual low temperatures at nearby Dulles Airport.

So, it’s going to be cold, but it’s in line with expectations.

Heat Pump:  Cold weather remains the soft underbelly of air source heat pumps.

 

I fully grasp the irony of heating my house with an electrical appliance that, by design, quits working when it gets really cold outside.

Near as I can tell, all air source heat pumps all do this.  It’s just a question of how low can they go.  What I think of a “standard” home unit, as I recall, shuts down around freezing (32F).  Conversely, the “high heat” versions of the heat pump I got will go down to -17F or some such.   Mine — the regular versions — stop working at 5F.  This — super cold weather — is where ground-source heat pumps shine, as the ground loop temperature may be quite cold by that time, but nowhere near as cold as it is outside in a cold snap.   So the ground source is starting from much “warmer” material to extract its heat from.  Which, as you might well imagine, is an enviable position for a heat pump to be in.

But.

But 1, I didn’t think I’d hit that lower temperature limit the first winter I owned the thing.  The lower limit for mine is, in fact, 5F.  So, I will be looking at some (brief?) period when this new air-source mini-split may not run.  Not because it’s broken.  Just because it’s cold outside.

But 2, now I have to suss out the secondary heat.  Every heat pump system has secondary heat, I think.  (Or maybe it’s “should have”).  That’s what you use when the heat pump isn’t enough.  (Or to speed up the heating of rooms, when the heat pump alone would raise temperatures too slowly.)

Secondary heat for this mini-split is strictly DIY.  That’s by design.  It doesn’t come with — nor is is capable of activating — secondary heat of any sort, as far as I can tell.

So, just burn some natural gas …

White Clouds in Blue Sky ca. 1996

Secondary heat isn’t really a problem, because I can burn natural gas for heat.

But.

But 1, I can only do that — use the baseboard heating in that part of my house — by jury-rigging what’s left of my (still kind-of functioning) baseboard hot water heating.

But 2:  My fancy gas water-heater/furnace objects to serving as mere house heater.  (Another long story.)  It’ll work, but it’s bad for the device (as in, this is what burnt out the internal pump motor the first time.)

So I’m going with something simpler.

Buying a small quantify of firewood in the dead of winter.

 

I am now that guy.  That guy who is … per the title.

I wanted more than a shrink-wrapped bundle. But far less than a cord.  Where can I buy that, around here?  Preferably to pick up.

The right place for that turned out to be the Reston Farm Garden Market.  Where I paid $85 for an eight-of-a-cord, kiln-dried, stacked (by them) into the back of my hatchback Bolt.

So, $680 a cord, for kiln-dried hardwood, bought in small (one-eighth-cord) quantity.  I thought that was OK, in an area where a cord of kiln-dried hardwood, delivered, from my nearest source, would run $550 plus delivery fee.

Kiln dried or merely seasoned?  We go for kiln-dried now. It guarantees that it’s good firewood, but it’s a little too good. For sure, it burns more readily.  There are no bad logs.  But it burn faster and hotter than it ought, which means messing with the draft and relying on the air-tightness of the stove door gasket.  (FWIW, I’m convinced that the hotter burn nearly makes up for the fossil fuels used to dry the wood.  So the kiln drying step is not quite as much of an energy loser as it might seem at first.  And with all the pests harbored by firewood, it has to be kiln-dried to be moved more than a county or two away, anyway.)

FYI, the various shrink-wrapped or netted bundles of firewood for sale at local retail stores seem to work out to around $1600 a cord.

Apparently, this little out-of-the-way farm store moves tractor-trailer-loads of firewood, per year, through their yard.

That said, local air pollution aside, firewood is an expensive way to heat my house, given prices in my area.

As I recall, this is about what I found the last time I figured it.  Recognizing that for me, electricity is cheaper than natural gas, this means that firewood is my most expensive fuel option.

Short of this:

With the understanding that I’ve already shown that electricity remains my least expensive fuel, almost regardless of the outside temperature.*

* As long as the heat pumps will run.

Conclusion

My wife and I agree that there is just something comforting about having a full rack of dry firewood.

It’s not rational, practical, economical, or conducive to the public health.

But it is comforting.

And firewood is going to provide our secondary heat through this cold snap.  For the occasional night or two when we hit the extreme winter lows for this climate zone, it seems like the easiest solution.

Post #2082: One-in-1000 Californians just lost a home?

 

I started off trying to get the LA fires into perspective.

I just want a back-of-the-envelope number

 

I hate to sound blase, but, OK, parts of LA have burnt.

Not wholly unexpected.  Surely more likely to happen as climate change progresses.

But, it’s, you know, California.  Stuff happens in California.  Earthquakes.  Mudslides.  Wildfires.  Excess rain and snow events.  Droughts.

I’m from the Mid-Atlantic region, where the worst we typically face is 17-year locusts and the occasional dry spell.

And this is in no sense a slam on California.  California is about as good at dealing with stuff like that as can be.

I just want to know something along the lines of “how does the value of the damage from the current LA fires compare to other disasters?”

I’ll settle for a count of homes lost to fire

Source:  fire.ca.gov.  Cal Fire?

As of 1/16/2025, the overwhelmingly quoted number in news coverage is 12,000.  That appears to be from 12,300+ “structures destroyed”, from Cal Fire.  As I understand it, that’s a number from the government of the State of California.

At the same time, a couple of big local banks (Wells Fargo and Goldman Sachs, cited by ABC News) have already projected $30B in insured losses.

If that projected $30B cost is close, these LA fires will be by far the most expensive fire event in California history, more than twice as expensive as the (now) second-most-costly fire in California history, the 2018 Camp Fire.

Source:  Cal Fire statistics page, this is their top 20 list.

By the numbers, it’s clear that a high cost per structure contributes to the overall higher cost of the LA fires, compared to the Camp fire.  To know that the loss estimate for the 2018 Camp Fire was $12B (reference).  That the works out to a $600K cost per structure for the 2018 Camp Fire — the costliest California fire until now — versus about $2.4M per destroyed structure for the LA fires.   I’m not sure I fully understand why the difference would be that large, but that’s what the simple arithmetic says.  Bear in mind that the $30B estimate is just a preliminary estimate by a couple of big banks.

 

13.4 million households in California

So says the U.S. Bureau of the Census (reference).

If the Los Angeles area just lost 12,300 plus structures, and if all of that was housing, and assuming (the equivalent of) predominantly single-family homes, then, roughly speaking, (12,300/13,400,000 =~) 0.1% of California households just lost their place to live.

If I had to take it further, it looks like Californians on average pay about 0.4% of the value of housing as insurance premiums each year.  Inverting that, this one event — a total loss of 0.1% of California housing — would seem to amount to about a quarter-of-a-year’s property insurance premiums for the entire state of California.  But because those LA properties appear to be so expensive per dwelling, it’s entire possible that this one even could cost … about a year’s worth of property insurance premiums for all of California.

Conclusion

A plausible scale of insured costs of U.S. natural disasters puts 2005 Hurricane Katrina at #1 with more than $100B (reference).  That’s in current (2025) dollars, roughly speaking.

The $30B projected insured losses for the LA fires would put them 10th on that list, just past the 1994 Northridge earthquake, the one that shook down a section of freeway.

It’s California.  I’m sure they’ll deal with it about as well as it can be dealt with.

Post #2079: So, when will Greenland be ready?

 

To use, I mean.  For us to use.

Now that it’s on order.  Once we buy it, or take it, or whatever.

How long before we get to use it?

I appreciate the sentiment.

Republican policy, if I can infer such, is not merely to ignore global warming, but to encourage the consumption of fossil fuels.

And yet, even as they deny it, they seem to realize they’ve got to have a place to put people.  You know, once Florida is under water, the Great Plains have reverted to sagebrush desert, and so on.

But, we’ve got this big empty island, just offshore.  Kinda.

Buy the big empty island, set up resort destination with a few casinos, and problem solved.

It’s a no-brainer.

Plus, if we’re tired of NATO, there’s no better way to do away with it than to attack a NATO country.

It’s a no-brainer and a two-fer.

But I digress.

How long for the ice to melt?

At present, Greenland is 80% covered by a remnant of the North American ice sheet.  It’s a relic from the most recent ice age.  I vaguely recollect that the ice is two miles thick in places.

But on average, it’s under a mile-and-a-half thick.

 

Based on all sources available to it, Google’s AI thinks it’ll take at least 1000 years for the ice to melt.

If I specifically narrow it to the IPCC, Google tells me “a few thousand years”.

Admittedly, some real estate will open up before the ice melts fully.

But given the overall time line for global warming, and certainly the likely remaining lifespan of the USA, I don’t think the ice up there is going to melt in time to do us much good.

 

Post #2077: I opened the hood of my car.

 

Finally.  I finally opened the hood of my 2020 Chevy Bolt, a year after I bought it (Post #1924).

I never saw a reason to look under the hood, figuring I’d have no idea what I was looking at.  It being an EV, and all.

Now that I’ve opened the hood, I was not disappointed.

Not ringing a lot of bells with me.  I think I recognize a brake master cylinder and tan plastic reservoir mounted to the firewall, driver’s side.  But all those big metal thingies?  No clue.

Luckily, one can be ignorant and still drive a car.  That, proven daily, I’d say.

Even now, I wouldn’t have bothered to open the hood, ever, except that with the recent winter storm, and the resulting sloppy roads, I figured I should top off windshield wiper fluid.  Seeing as how that hadn’t been done in a year.

I was able to do that without reading the manual.  The hood release was in an obvious place, the hood emergency latch was easy to find, and (shown below) the right place for windshield wiper fluid is pretty clearly marked.  Even had a hood prop where I expected to find it.

So thumbs up to Chevy for making that much obvious.

Weirdly, I swear there’s a fan and radiator in there somewhere.  For sure, there are several little reservoirs that look like they hold coolant.  Plausibly that’s all part of whatever manages the temperature of the battery and the electronics.

It’s magic, as far as I’m concerned.

Plus it runs at a lethal 350V DC.  As long is to works, leave it be.

And pour carefully.

Post #2076: Snow day.

 

Today, Monday 1/6/2025, is a snow day.

From the sound of it, at 7:45 AM, we’re getting wintry mix here in Vienna.

It’s our favorite form of winter precipitation.

Can you keep yourself warm by burning sticks in your wood stove?

Yes.  Give me enough sticks, and I will stay warm indefinitely.  Proven.

But no, I’m never going to do this again.

Above left, note wheelbarrow full of (dry) sticks.  I started this winter with several such, along with a few trash cans and plastic totes full of similar material.  That,  courtesy of taking down a couple of small trees in my yard this past summer.

Above right, is the modern wood stove insert, with blazing fire made out of sticks.  Sticks, obviously, broken small enough to fit into the firebox.

Above, between, are the almost-empty firewood racks.  So there’s no doubt that it’s the sticks I’m burning.  And note the two fire extinguishers.  Because nothing says fun-at-home like a blazing fire right next to a big, loose pile of kindling.

I have no problem bringing my wood stove (insert) up to a good operating temperature by burning loads of sticks, instead of nice chunks of firewood.  In fact, dry sticks burn too well, so some of the work is keeping the fire down to a reasonable size.  No problem keeping it that hot for hours, with the circulating fan pumping hot air out into the room.

It’s just a real pain in the butt to maintain that fire.  Not quite a full-time job, but hardly a relaxing fire.  I have to toss in another handful of sticks every 15 minutes or so.  And it’s fiddly, with a handful of sticks being a less stable fuel source than a solid chunk of firewood.  Keeping a fire going with nothing but sticks is nothing at all like putting a couple of logs in the firebox once an hour.

I’m going to burn through the rest of my stock of sticks in the next couple of nights.  Then I’m never going do to this again.  This, being, burn up a large amount of small branches in my wood stove.  Not worth the effort, the indoor air pollution, and so on.

But, if I had to stay warm, and had no firewood, it’s good to know that a wheelbarrow of sticks will get me two, maybe three, hours of usable fire.  Burning it an open handful — call it a 5-inch bundle — at a time.

Conclusion

My wife and I were both reminded of that part of Little House on the Prairie, The Long Winter, where the Ingalls family stays alive by constantly feeding sticks of twisted straw into their wood stove.

I absolutely can produce a fine quantity of heat by feeding a steady stream of bundles of sticks to a modern (air-tight) wood stove.

Or, I could just turn up the heat pumps.

In any case, as a way to get rid of nuisance wood, to some good purpose, this is fine.  Or, if it were an emergency, likewise fine.

But doing this on purpose, now that I’ve done it once?  Nah.  Too much work, too much indoor air pollution.

I’ve thought about buying in more firewood, but for a lot of reasons, I’ve decided not to use my wood stove as a serious source of heat any more.  Not here in the ‘burbs of DC.

Maybe it was the Canadian forest fire smoke of (now) two summers ago, maybe it’s that I have a much-reduced need to “balance” heating and cooling from my ground-source heat pumps.

I will still burn wood occasionally, I guess.  And it’s nice to have as an ultimate back-up heat source.  But I’m no longer going to do what I used to do, which is burn through a couple of cords of wood over a winter.

But now I know I can keep my house from freezing, by burning sticks in my wood stove.

Yay?  I hope I never need to know that, practically speaking.

Post 2060: My life with a two-headed three-ton ductless mini-split.

 

I’m now the owner of a two-headed three-ton ductless mini-split.

And lovin’ it.

 

Pictured above:  Those boxes, on the wall, are the inside portion of my new ductless mini-split heat pump.

They blow hot air.  They blow cold air.  When you ask them to.  One per room is adequate, unless you dwell in a house of unusual size.  And one per room is required, if you want heat (and AC) in that room.

The outside, it’s about as attractive as you would expect, for a heat pump.  Slightly uglier than a standard system, owing to the need to run refrigerant and electrical lines up the outside of the house, to each of those interior boxes, connecting to the compressor unit at ground level.  Here, the line covers (the things that look like aluminum downspouts) blend right in with the electrical, phone, FIOS and whatnot already hanging off the vinyl siding at that end of the house.

For me, they were less expensive than my closest alternative. I paid $13K installed, $11K after the Federal tax credit.  If I’d replaced my dead ground-source heat pump, it would have been $25K, $17.5K net of (a much higher) tax credit.  I picked the contractor based on reputation, on a friend’s recommendation, and on the fact that we were immediately on the same wavelength, regarding a nice, simple installation.

Mine is a three-ton (36000 BTUH) compressor, hooked up to two 1.5 ton heads.  Took a day and a half to install, but the HVAC guy was training a couple of guys, so a one-day install would not have been out of the question if I’d been in a hurry.

These Mitsubishi units will produce heat down to 5F.  Below that, I think they automatically shut off.  At 5F, their heating efficiency will have fallen to the point that they were merely twice as efficient as an electric space heater (COP 2.1), instead of 3.5 times as efficient (COP 3.5) at 47F.

The same company (Mitsubishi) that makes these makes a “hyper heat” compressor that will run at outside temperatures down to -13F, but the outside pieces (the compressors) for those run about twice the cost of a standard compressor, near as I can tell.

We got a standard unit that’ll only function down to 5 degrees F.  But, thanks to global warming, that should do us, as this decade’s USDA hardiness zone maps bumped us from Zone 7A to 7B, meaning that 5 F is not a bad guess for the lowest temperature we’ll ever see here, ever again.  And if not, the old gas-fired hot water baseboards still work.

On paper, they’re as efficient as any other option I could get, including ground-source heat pumps.  I did an entire post on that earlier (Post #2032).  Once I got up an apples-to-apples comparison, the near-equality was obvious.

For typical winter temperatures around here, these ought to run at around COP 3.5, or, as noted, three-point-five times as efficient as an electric space heater.  In practice, they look like they’re going to do even better than I thought, owing at least to their “inverter” continous-speed technology.

I get the distinct impression that these heat pumps, with their variable-speed compressors and blowers, like being operated for long periods of time, at a relatively low load.  So I’m rethinking my life-long habit of nighttime temperature setbacks to save energy.  Don’t now what the outcome of that analysis will be.

The only thing you really need to install one is a place to put the compressor (near where the inside heads are), and some way to run a 220V electrical line there.  The electrical power for the interior heads is routed through the outside compressor unit.  So the electrical lines for the interior heads run right alongside the refrigerant lines.

And you need to have an empty 220V breaker in your electrical panel, of about the right size.  This three-ton unit needed a 25-amp breaker.  The installer just pulled the wires out of the breaker for the now-useless ground source unit, and put in the wires powering the new one.  The legally-required outside electrical cutoff comes with surge suppressor built in.

The refrigerant is R410A, which seems to be the only option for any HVAC equipment that I could buy.  It has greatly reduced ozone-depletion potential relative to old-school Freon (R22), but it’s still a potent greenhouse gas.  Less than ideal, but that’s what commodity heat pumps are using.

Some background follows.

 

Ductless mini-split.  A product clearly named by its competitors.

It’s just a normal heat pump.

The best way to describe it is by contrasting it with “normal” central heating/AC.  For a single-family home, the typical central heat/central AC set up is:

  • one hot/cold coil in the house
  • sitting inside a blower housing
  • typically in your basement or attic,
  • blowing conditioned air into your ducts, and from there to all the rooms of your house.

A mini-split is decentralized heating and AC, as far as the inside of the house is concerned.

  • one hot/cold coil in each room,
  • sitting in its own stand-alone blower cabinet,
  • blowing conditioned air directly into the room,
  • and so cooling or heating that one room.

Outside, by contrast, a typical mini-split system is more-or-less the same as central heating systems.  For reduced installation cost (and, I’d bet, better operating efficiency), you run multiple mini-split “heads” off one outdoor compressor unit.  This then requires you to run multiple sets of refrigerant lines to that one compressor, as opposed to the one set that would run to the compressor in central (ducted) forced-air system.

You pick the combination of outside compressor and inside head(s) to give you what you want.  My outside three-ton unit can take from two to four heads, as long as the total “ton” capacity of those heads is three tons of cooling (36000 BTUH).  Available compressors and heads both span a range of tonnages.

Nothing about the name “ductless mini-split” is even the tiniest bit helpful in understanding what it is.

First, it’s not mini.  It’s a full-sized HVAC unit, in terms of heat and cooling capacity.  Ours is a “three-ton” unit, meaning 36,000 BTUs/hour cooling capacity.  This is roughly the same as the heat pump it replaced.  In this climate, that’s enough for a small house, or, in our case, the first floor of a larger house.

The only “mini” part is that these units have compact, quiet outdoor part.  Two strong men can lift and carry one, and just bolt it down in place, as a unit.  So they are mini, in that the outdoor (compressor) piece of this isn’t a big louvered metal box that makes a hellacious racket when the AC or heat pump comes on.  Which is the tradition in the American ‘burbs.

Second, split just means “normal”.  As in, there’s an inside part, and an outside part, and some refrigerant lines and wires connecting the two parts.  Just like every suburban home central AC that you’ve ever seen.

Arguably, the only AC system you’ve ever seen that isn’t a “split” unit is a window air conditioner.  There, the outdoor and indoor components are in the same metal box.  But any home central AC you’ve ever seen is a split unit.

(And I now know why “split” is even a thing, for HVAC contractors.  For ground source heat pumps, you actually do have an alternative to split units, called “package” units, where the heat pump and the air handler (that blows the heated or cooled air into your duct work) are combined in a single box.  These units get a generally higher efficiency rating than split units, but I never did decide how real that was.  It almost seemed as if that might be a side-effect of the way these were tested.  Anyway, split versus packaged matters for ground-source heat pump options, but pretty much for nothing else having to do with home HVAC.)

Third “ductless” just means that the part that blows air around your house is a self-contained blower unit.  Typically, the “head” resides in a plastic cabinet, mounted high on a wall, as above.  But you can get them as console-type units.  Or as units that recess into the ceiling.  (And there are, in fact, ducted versions of these, where they are set up to be connected to a set of duct.  But that’s not their selling point.)

Not pushing air through ducts gives these a modest energy advantage, all other things equal.

But a downside of “ductless” is that there’s no air return in this system, as there is an a traditional central forced-air system.  Air does not flow out of the ducts, toward the return.  It just flows out into the room its in.  That limits these to heating essentially one open space per head.  OTOH, these units seem to have no problem throwing warm air for a considerable distance.

It’s a different heating and cooling gestalt

In the typical central forced-air heat or AC system, you blow air out the ducts, and suck it back up in some distant central air return.  This means that air flows through all the rooms, and you can count on that air flow both to mix the air, and to make the conditioned air travel the full distance from duct outlet to return inlet.  Ideally, the result is a uniformly heated or cooled living space, and no apparent breezes.

A ductless mini-split is a different beast entirely, and no nearly so elegant as central forced air.

There’s no air return.  This limits the “throw” of each unit to the space in which it can manage to blow its warm or cold air.  The result is that a) you definitely get a warm breeze if it’s really cranking, and b) the air temperature in the room is not as uniform as it is with central forced-air systems.

Neither of which bothers me in the least. I actually like both aspects.  And mine are strong enough to heat the living-dining room from one end to the other, which has to be 30-some feet.

The upshot is that if you want nice, uniform, breezeless heat throughout a room, these are not for you.  As far as the user is concerned, these are more like having the best space heater you’ve ever used, hanging on the wall of your house.  It works well, but not as nicely as a properly-configured central forced-air system.

(N.B., a 1.5 ton head is 18,000 BTUH, which equates to the heat you’d get from about a 5000-watt resistance space heater, where the biggest plug-in 120V space heater you can buy is 1500 watts.  The astute reader will recognize that 5000 watts at 120V would be … way more electricity than the entire compressor uses, if it sits on a 25-amp breaker.  Which is neither a violation of the laws of physics nor magic, but the whole point of using a heat pump, because the coefficient-of-performance (COP) is bigger than 1.0.  You do, in fact, get more heat out of it, than is embodied in the energy it takes to run it.  Because it’s not a heater, it’s a heat pump.)

 

The back story

In 2004, the previous owner of my house had a ground-source heat pump system installed.  Mile of pipe buried in the back yard, hooked up to two heat pumps, retrofit to the existing duct work, using the existing hot-water gas-fired baseboards as secondary heat for the heat pumps.

(Secondary heat is the additional heat source the system turns on if it looks like it’s taking too long for the heat pumps alone to bring the house up to temperature, or maintain temperature.)

In 2007 we bought the house thinking, neat, that’s the most efficient heating we can get.  Only after we lived with it for a while did we fully appreciate what a botched Frankenstein’s monster our heating system was.

This 1959 home was an energy use nightmare.  (Ah, bad dream, maybe.)  Rather than insulating the attic and ceiling spaces, or dealing with the huge air leaks, or the (believe-it-or-not) uninsulated walls, or the four big open fireplace chimneys, … the previous owner figured he’d just install his high-tech redneck heating system and be done with it.  And botched that install in several important ways, to boot.

For example, I ask you, what sane home buyer looks at a nice new high-end kitchen remodel, stone countertops, cherry cabinets, stainless high-end appliances and says, that’s a very nice kitchen, but, does that come with heating and cooling?

Because in my case, the answer was no.  They tore out the old hot-water baseboard heat and, to a very close approximation, replaced it with nothing.  Which, as the owner, you don’t really figure out until winter sets in, some time later.

What sort of person would do that, in their own kitchen remodel?  The same sort of person that did all the rest of the HVAC system.  Near as I can tell, absolutely no aspect of it was planned or executed well.  Let me omit the rest of the kvetching by saying that it has never worked well.  And the kitchen is always ass-freezing cold in the winter.  And that, upon closer inspection, that last problem seemed un-fixable.

So we let Frankenstein be.  And did a lot of baked goods in the winter.  Slow-cooker recipes.  And so forth.

FF to 2024.  The ground-source heat pump for the first floor is dead,and the one for the second floor is failing.  And I wasn’t shedding tear over its demise, given the miserable performance.

Until, that is, I found out it was going to cost me $50K to replace them.

But there’s nothing like a pending major expenditure to sharpen your focus, if not your wits.  For various reasons, my wife and I decided that it was stupid to spend $50K to repeat the previous owner’s mistakes with fresh equipment.  And that maybe, just maybe, for the first time since we moved in, we could actually have a warm kitchen.

Our solution was to ignore the dead ground-source heat pump, ignore the grossly under-sized duct work, the cobbled-up secondary heat, the @#@#$ wireless thermostat that worked sometimes.  Rather than try to work around the same problems that the last guy was unable to fix, we decided to start fresh with an air-source ductless mini-split that had nothing whatsoever to do with the existing Frankenstein of a system.

And that’s how we ended up here.

Post #2036: Replacing my heat pumps III: The tax angles.

 

Winter approaches. 

But no pressure, as I slowly work through the tax angles on this HVAC equipment replacement decision.  And bring somebody in for another quote for new equipment. And maybe, eventually, get everything working again.

If nothing else, this whole episode shows me that it’s good to have multiple heating systems in your home.

Even with one heat pump dead, we have some heat.

And that is way better than no heat. Continue reading Post #2036: Replacing my heat pumps III: The tax angles.