Even Tantalus Wouldn’t Drink That

Even back before I knew I wanted a heat pump, and a pony, I knew I wanted to handle some air. In HVAC, this is usually handled by an air handler. Duh. That’s a big cabinet-looking appliance with a big fan in it in most people’s houses. If you have a standard furnace, the unit itself usually functions as the air handler too. You burn some sort of gas or goo to heat up some air and then you blow it through some ducts hither and yon around your house. Boilers do the same sort of thing, but they heat water instead of air, and circulate that around.

Well, I was producing hot air without the goo already. I”m nor referring to blogging here. I was burning pellets in a big stove and dumping the hot air in the dining room. Luckily, the dining room was more or less centrally located, but heat takes some persuasion to get it to go to where you want it. The little 200CFM fan in the back of the pellet stove wasn’t going to spread it around 2,000 square feet of house. We didn’t (don’t) have the money for a proper central heating system, so we resorted to our default guerilla warfare approach to the problem.

Way back when, I outlined our scheme to get heat from the dining room upstairs into our children’s bedrooms in The Tin Man’s Autopsy. We couldn’t afford an air handler, but we could put some tin pipes between floors to coax the heat upstairs.

Then I painstakingly explained Eight Things That Won’t Happen in Heating, to outline why I was doing what I was doing in the manner I was doing it, but I freely admit I did a lousy job explaining what I wanted a pony for. This HVAC explanation was roundly ignored by several people in the comments, who love them some ceiling fans, and the rest of the internet, more or less. After a somewhat charming lagniappe filled with my children’s music videos and earnest pleas to my wife not to leave my sorry ass even though I didn’t get her a pony for our anniversary, I finally got around to Let’s See if Sippican Can Tie His Heating System Into His Sewer System.

Of course everyone immediately lost interest in my ersatz air handling explanations and glommed onto the Geyser of Excrement tale. I know I did. In the world of construction triage, fixing a problem with not enough BTUs floating by comes well after stopping merde floating by in the basement. You can read all about it at the link, if you like. Lots and lots of people have. It’s a testament to what’s important in this online world that the most notable thing I ever wrote was about just how full of shite my life had become.

But ignored in the scum scrum was the fact that we did actually solve our air handling problem, albeit incrementally, not exponentially. We installed ducts up high in the dining room wall, and ran them up into the second floor. It’s all achieved inside of closets, a happy accident of floor layout. The inlet pipe was up by the ceiling in the dining room. There were two outlets upstairs, one for each kid’s bedroom. We simply stood a regular tabletop fan on top of the big cabinet that once stood there, and it blew the heated air upstairs. It wasn’t a pony or anything, but the kids still liked it.

I had bought enough tin to make a cold air return as well. I planned on recovering cold air near the floors in the bedrooms upstairs, and dumping it through the floor directly over the pellet stove. It would make a nice convection loop, and make it easier to force air up the ducts into the rooms in the first place. It was a great idea that was not to be. When the geyser hit, I had to return the remaining HVAC ducts to the store to get a credit to apply to the cost of some of the plumbing supplies we were going to need tout de suite. I was Tantalus, but I wasn’t up to my knees in water, exactly.

But the seeds of inspiration were sown. I went into my closet and looked up, and saw ductwork heading upstairs. Then I looked straight down, and realized the furnace was directly below in the basement. From the inside of that closet, and the closet above it upstairs, I could picture ductwork coming straight up from the basement and serving the living room, dining room, three bedrooms, and the hallways and staircases on two floors.

It would take years of scrimping and saving, but I could see a way to heat the whole house with a central heating plenum and ducts running straight up through the center of the house, and not lose an inch of livable floor space in the bargain. It wasn’t a pony, but central heating would still be pretty good. Besides, I’m not sure a pony would taste all that good, even if we got our hands on one.

[To be continued]

It’s a Magic Show

I kinda decided I wanted a heat pump. After a decade of freezing in our hovel in western Maine, and shoveling tons of firewood into a furnace and pallets of pellets into a stove, I wanted a dial on the wall that you turned to have some effect on the temperature. I got old, or tired, or lazy. You decide which. I’m too old, tired, and lazy to figure it out.

You can, or you can’t have a heat pump in Maine, depending on who you listen to. The crux of the problem is that the people who tell you that it’s perfectly fine, even commendable to have a heat pump in Maine are wrong, and the people who say you can’t have a heat pump in Maine are wrong, too. They’re just wrong for different reasons. Don’t worry. You look worried. But don’t. I’ll explain.

The State of Maine wants you to buy a heat pump. They’ll sort of pay you to buy one, actually, in the form of rebates. Here’s a not very exhaustive list of the sort of rebates on offer, if you’re interested. I wasn’t.

What this meant in practice is you got a coupon for a discount on a ductless minisplit heat pump. Ductless refers to the way it’s set up to produce heat or air conditioning. There’s a compressor outside with a big fan and lots of coils in it. There’s a “cassette,” a large-ish plastic radiator monstrosity you hang on the wall in a single room in your house. It burps out heat or cooling using a little fan. In between the cassette and the compressor, you run two copper refrigerant lines, a plastic drain hose (because the thing frosts up like a 1940s reefer), and a very substantial electrical circuit.

Of course, to get the rebate, you’re required to hire a certified (by the government) installer for your minisplit, who would immediately add the value of the rebate to the price you end up paying, because human nature isn’t (yet) controlled by the gov. Then they’d come to your house and hang an unsightly compressor on your house wherever was convenient for them, usually right by the front door, and then snake unsightly plastic chases (to cover the piping) all over the side of your house, till they arrived at the spot where they could drill a hole right through it. That’s the other side of the wall where they’re going to hang a big, unsightly cassette in one room of your house. Minisplit installers seem to all have been trained as cable TV installers in the past, as far as running new utilities goes.

They do make minisplits that serve multiple cassettes from a single compressor. If you’re in a Captain Nemo mood and want your house to look like it’s being attacked by a giant octopus, these are just the thing for you. But for the most part, Mainers just like the rebate, and use a single cassette leading to a single compressor as a replacement for a room air conditioner, and don’t use the heating function much. Most of Maine has zero cooling degree days a year, so you can anticipate how efficient giving residents rebates to overpay for minisplits has been to achieve their stated purpose, which is getting rid of heating oil as a primary heat source in the state.

So those are the people who tell you that making 12,000 BTUs of heating and cooling and dumping it in one spot in your house is a substitute for your 75,000 BTU oil furnace and ten miles of ducts or copper pipes. They’re wrong, but they’re not the only kind of wrong. The other faction tells you it’s too cold in Maine to have a heat pump. They say they’re just for air conditioning in Tallahassee, and that’s that.

That’s a whole different kind of wrong there. When the gov banned pesky chlorofluorocarbons in heating and cooling devices because the ozone layer got a bald spot, it set the refrigeration and HVAC industry back some. But they got busy and eventually found able substitutes. They put them in heat pumps now. Do try to keep up, people.

I’m going to give away the denouement of this little jag I’ll be foisting on you for days now, by telling you I have a heat pump, and here’s a chart of the temperatures it’s rated to work at:

It produces 36,000 BTUs of heat.

Well, it produces 36,000 BTUs of heat if it’s 68 degrees out. That’s a layup, of course. It ain’t hard to raise the temperature in your house by four degrees or so, is it? Heat pumps work by capturing heat from outside in recirculating coolant, bringing it inside, and emitting it by blowing a fan over some coils. When there’s lots of heat outside, it’s easier to bring a bunch inside.

Now let’s go back to the chart. The heat pump also produces 36,000 BTUs of heat when the outside temperature is 17 degrees F. The amount of heat it produces goes down from there, but the thing still makes 18,400 BTUs at 22 below zero Fahrenheit. The efficiency goes down, (see the HSPF column) but it still makes heat. It’s interesting, but 22 below zero is the coldest temperature I’ve ever observed here since we moved in. So, it’s not too cold here for a heat pump.

You have to understand the HSPF rating, though. The Heating Seasonal Performance Factor (HSPF), is a rating that measures how much more efficient a heat pump is at using electricity compared to regular resistance electric heat. If you run electricity through a baseboard heater, it’s 100-percent efficient. That is, 100 percent of the electricity is turned into heat. It’s also 100-percent efficient in hoovering out your bank account. Electric resistance heat is the most expensive form of heat I know of. You may be burning Coach handbags in a hibachi to get your heat, I don’t know, but around here, everything is cheaper than electric.

Heat pumps don’t work like that. They use electricity to circulate coolant, compress it, and blow fans over some coils filled with the circulating coolant, both inside and outside the house. Those sorts of pumps and fans use electricity, but not nearly as much as simply heating metal fins by running electricity through them. The HSPF rating tell you how much more efficient it is compared to resistance heat. The bigger the number, the more efficient it is.

To figure out HSPF, you take the heating output in BTUs and divide it by the amount of electricity it took to make it. So to compare:

• If I put a watt-hour into a baseboard heater, I get 3.41 BTUs out of it
• If I put a watt-hour into a heat pump rated at 10 HSPF, I get 10 BTUs out of it

So even at 22 degrees below zero, a heat pump is still about 25% more efficient than 100% efficient baseboard heat. That’s not a heating device. It’s a magic show.

So it ain’t too cold here, but I don’t want an octopus on the side of my house. I still want to get up to 10 BTUs out of a watt-hour. What exactly do I want?

[To be continued]