this post was submitted on 01 Aug 2023
456 points (97.9% liked)
Technology
59472 readers
5116 users here now
This is a most excellent place for technology news and articles.
Our Rules
- Follow the lemmy.world rules.
- Only tech related content.
- Be excellent to each another!
- Mod approved content bots can post up to 10 articles per day.
- Threads asking for personal tech support may be deleted.
- Politics threads may be removed.
- No memes allowed as posts, OK to post as comments.
- Only approved bots from the list below, to ask if your bot can be added please contact us.
- Check for duplicates before posting, duplicates may be removed
Approved Bots
founded 1 year ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
It gets below zero in the north east in the winter. Heat pumps stop working at 20-30F and the system has to switch to classic/emergency heat. They are great for fall/spring (or summer as an AC), but useless for winter.
The bigger issue is that it is extremely expensive to install ductwork, wiring for 1 or more thermostats, and a shiny new heating/cooling system in many existing homes that use classic radiator heat. Depending on where the oil tank is located, it may require removal as well (example: if it is underground, depending on state/municipal laws).
That's not necessarily true now the newer systems can go to as low as -15F which in the north only happens for a few hours a year so still a reduction in heating gas/oils needed
I know the guy in the TC video used Chicago as an example but the "few hours a year" thing simply isn't true for many of us.
Where I live we had many days below -15f including a week where itpretty much stayed between -20 and -30 for nearly a week straight.
A Heat Pump will still work, even here, but you need to be careful about which one you purchase and how it handles cold weather.
Or remember when it "felt like" - 50° F for two days straight that one February?
I had to start my car up twice every night to keep the battery from dying.
I got a quote last year as my furnace is original to the house (33 years old) and we don’t have AC.
It was going to be $25,000, $5k of which was installing new ductwork because the existing ducts aren’t insulated enough.
Easy pass. I’ll wait for prices to (hopefully) come down.
It’s probably not gonna come down.
I’m in HVAC, the industry is insane right now with the cost of equipment alone, let alone the hourly rate for the installers.
Honestly, 25k for a complete overhaul is probably the lowest you’re gonna get.
I’d look into mini split heat pumps. Ditch the ducts all together, and you’ll probably save a few grand.
The last time I did a quote for a house in the northeast it came in at over 50k all-in. Oil tank had to be removed which would have costed a ton…the state would only pay for part of it. New ductwork run, baseboard heating removed (pipes sawed off and capped at wall), hot water heater added, new heat pump with dual zone + thermostats for upstairs/downstairs. Plumbing modifications for new setup including a new hot water line for reasons I can’t remember. Drywall ripped out, replaced, painted, etc.
3 different quotes for over 50k. I sold the house instead. No thanks.
My current place (not in the northeast) has a heat pump and our electric bill is never over $200 for a 2,200 sq ft home, so they will definitely save you money. That up front cost can be a killer, however. We had the heat pump stop working once and had to use emergency heat for about a month and our electric bill more than doubled.
Same in the UK. I'm looking at 20k and that's after the 5k grant. It has to come down a lot to be viable.. I just don't have that kind of cash.
First off, as the other poster replied, that isn’t true about modern heat pumps. They continue to work below freezing, and many support an “eheat” resistive heating mode, obviously only good if you still have electricity, but that’s true of all heat pumps. Generators or solar+batteries become much more important.
But the beauty of heat pumps is that you don’t need to install ductwork. Look at mini splits. You can do zoned or single room installs. No ductwork required. One of the huge upsides of mini splits are you do get “instant” zoning. You can stop heating and cooling unused rooms to a human comfortable temperature.
You can also get systems that retrofit into existing forced air ductwork.
I wouldn’t be surprised if someone made or will make a heat pump water heater for hydronic radiators.
You can also run the element that is typically outdoors inside if you have enough space in a basement, for example, which stay a pretty consistent temperature all year long.
Man this was a wild ride on this comment chain. At first I was sad, because I don't have ductwork, now I am excited because I was eyeing a mini-split for our AC anyway. Yay!
Yeah, just get one with reversing valve so you can switch between heating and cooling cycle. Well more like switch around where the heating an cooling cycles happen.
Minisplit doesn't matter since actually almost all of the process happens on the outside unit. What goes inside is the fluid lines(refrigerant feed and return), condensation water line out from the inside and a control data cable from the inside blower unit to the outside operative unit. Outside unit switching around what stage of the fluid cycle gets fed to the inside going line, changes purpose between cooling and heating. Oh yeah and the inside unit also has an electric fan and nozzles to make the airflow happen.
edit: What often mislead is people designating one and other of the coils as evaporator and condenser depending on choosing which mode is "default". Even manufacturers materials. However with 4-way diverting valve unit there is no dedicated evaporator and condenser. There is just two heat exchanger coils. Inside located coil and outside located coil. It is completely upto the valve position and flow diversion, as which is which. Each is always one or the another, but which is which is depending on the valve position. The system is equally as happy air-conditioning the outside or the inside. Thus in match heating the inside or the outside.
Heat pump and AC are the same thing. AC is just specific name for use case of heatpump, where the cold coil (evaporator) is inside and the hot coil (condenser) is outside.
Wait a minute... so I can just turn my window unit 180 degrees in the winter? Joking... sort of. Would that work, at least for a while (in theory, I am not actually weird enough to try it)
It probably wouldn’t run because the air its ingesting to cool is already cold, but if you bypassed the thermostat, sure.
Because they’re not designed to work that way I’m sure their efficiency would be low/non existent in actually cold temps.
Early heat pumps could only work to like 30F or so. New ones are much, much better.
Well it would probably "pee" on your floor. Since typically window unit air conditioners have condensation water tube going to outside edge and just letting it drip out. The condensation water after all has to go somewhere. Minisplits actually usually have a third line going out for that along with the refrigerant lines. Fluid in, fluid return and then condensate waterline for, when the inside is cooling and thus generating condensation.
Otherwise? It probably isn't winterized, but theoretically.... heat pumping is heat pumping. It would try to cool the outside air and thus heat inside. Though its thermostats probably would need tweaking. Don't think those have setting for "please cool down to -15C". Meaning in practice it would never run, since ambient already is constantly below its minimum temperature. Though as I remember most arcane old units didn't have such fancy feature as thermostat. You just turned them on, they would pump at their full capacity constantly and you were yourself supposed to be the thermostat by turning the power switch off, when you didn't want any more cooling.
How does that work then.. I get it for the portable ones, you stick the pipe out of the window, but last time I priced up a mini split it was more than twice the cost of a single room due to the installation work involved. There has to be ducting, they're not magic..
You drill a small hole and run some hoses outside from each room.
It’s definitely more expensive than a window air conditioner, but a lot quieter and more efficient, and provides heat.
Yeah crappy ones. This does not apply to the ones designed for cold climates. Mine still beats electric radiators in efficiency at -22f
That is refrigerant dependent. For example R744 (plain old CO2) works well efficiently down to -4F, -20C and down to -40C/-40F just with some efficiency drop.
Main issue is CO2 needs a constant high pressure heat pump system, since it needs to be highly pressurised to be fluid at all. In ambient it sublimates (goes straight between gas and solid aka dry ice).
However that is a solved issue. Working CO2 heatpumps are off the self commercially available these days. Just still little more expensive as I understand. However prices should come down with production economies of scale, upon CO2 taking over due to pollution, toxicity, flammability, green house considerations. He nastier chemicals weren't used for being all the ways superior, but due to it being easier to make the heat pump units (be they running in heating or in cooling) due to lower pressure requirements.
Since CO2 and ammonia were the original refrigerants. Used in large ice production facilities early on, where their specific needs weren't issue even for earlier technology. Large, purpose built, stationary industrial facility had no problem accommodating the needed massive pressures by just really massive and heavy pipework.
However these days the propeller head people developed micro channel tubing and heat exchangers to keep the high pressure CO2 in control.
In Scandinavia we run ours down to -4F or colder. Efficiency goes down but they are still better than 1:1 until then.
Average temperatures for Bangor, Maine in January are colder than the average temperatures for January in Stockholm, Sweden.
Bangor
Stockholm
Still within range of a good heat pump but Scandinavian countries don't have a lock on cold. January averages where I live in the US are colder than Reykjavik, Iceland!
Well.... Iceland has ocean warmth due to gulf stream and is a literal vulcanic Island. Heck Island doesn't have heating problems, they just capture heat from the hot springs created by the vulcanism.
As such Iceland is kinda misleading as is Greenland. Iceland has less ice than greenland. Though Iceland is not green, more like black given all the volcanic basalt.
Average January temps where I live are lower than Stockholm. I chose Reykjavik because it's a neat place, not because it was particularly cold. :)