this post was submitted on 11 Mar 2024
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Heat Pumps are just Air Conditioners with a reversing valve. They're not some special magic.
Increasingly, they also tend to have variable-speed compressors, which offer further efficiency benefits. I think the distinction between A/C and heat pump is useful for consumers.
Just got a Bosch Inverter (variable speed) last summer, and the remainder of the summer and through the winter, my electric usage is down by about 30% over last year's even though I lowered the thermostat temp in summer and increased it in winter.
Old system was 20 years old. I was hoping to see some ROI after this surprise expense, and it has exceeded expectation so far.
You could add end-of-life solar panels and an automatic transfer switch and save a lot more.
If only! I have a condo in an HOA neighborhood, so no outdoor goodies.
Get on the board and make everyone do it.
Hey, pedant here.
Air conditioners are heat pumps too, and it's not the reversing valve that differentiates them. Heat pumps move heat, reversing valve let's you decide which way to move it.
That's exactly what I said. Air Conditioners are heat pumps which only pump one way.
No you said heat pumps are air conditioners which is wrong.
Heat pumps are a technology.
Some are used as air conditioners, some are used as heaters, some as both. Some are used for heating liquids, some are used for cooling foods. They simply move heat from one location to another, application and reversibility independent.
All heat pumps are air conditioners. Not all air conditioners are heat pumps.
Nah you're arse about. It'd be like saying all internal combustion engines are generators.
Engines just drive things, like cars, generators, lawn mowers etc. They're a technology for rotating something.
Heat pumps are just a technology for moving heat.
Not going to reply any further as unsure at this stage if you're trolling. Literally just go read the Wikipedia page on heat pumps.
I like pedants. Is it correct that they're not necessarily equally efficient in both directions? "Air conditioner" to transfer heat away, vs "heat pump" to transfer heat in? Even though both are heat pumps.
Sort of... It's not so much down to it just not working as good at transferring heat, because the rules of thermodynamics applies... moving heat is moving heat.
But the devil's in the details. If it's below freezing the radiator will frost up and won't work very good. But that problem is solved by temporarily reversing it to heat of the radiator to melt the frost off of it. These systems do this automatically. Freezing temperature is 273 Kelvin, so there is heat outside even when it's below freezing so there's always heat that can be pumped, but there are limits to it.
You don't want to be dependent on a heat pump as the only source of heat for your house. But they build electric heaters into many models to handle those conditions. But obviously on really cold days that it needs to supplement the heating with the electric heater it's not going to be all that efficient, because you're running an electric heater on those days.
But most days it's not going to need to turn on the electric heater, and on your cool spring and fall days it won't even need to defrost. So when you consider it over the course of a year, the heating cost is way lower.
Thanks! I like you space cowboy.
High pressure refrigerants are making the temperature differential higher, so the need for resistive heating is going down.
Can you convert an existing AC system to do both and save money on getting a whole new system installed?
It's probably not worth it. If you have a system more than 10 years old, then you're probably going to have to replace the accumulator as well if it uses a different kind of refrigerant. It's likely cheaper to buy a whole unit and furnace than messing with it.
What about a new system? Had the AC compressor replaced last year but not the gas fired furnace due to cost lol
I believe so but you need a new compressor - the heat exchanger in the house can stay the same I think.
You have a furnace that provides heat, air handler that moves the air, and compressor that forces heat in a certain direction (inside to outside in the case of AC) with coils in the air handler to make use of that (re)moved heat.
Heat pumps have several features that make them a bit more than backwards AC, like defrost systems, VFDs and often dual-fuel controls. If it snows where you are, you'll also want it off the ground. So, best to get a new system.
As another said, you might be able to reuse the coolant lines and coils in the air handler. It might not be a bad idea to keep the furnace for backup when it's extra cold.
so why do they have to cost 4-5x what it costs to get an Aircon installed?
I posted this elsewhere in this thread, but here seems good too:
Obligatory Technology Connections ( @[email protected]): Old HVAC industry practices are holding us back and costing us money. But we can fix it.
TL;DW (but you really should, it's a great video): "Recommended" heat pumps are often oversized and overpriced compared to what is actually needed, and homeowners need to be aware of this.
Condensed version
Lobbying, probably.
Heat Pumps are just Air Conditioners with a reversing valve. They are some special magic.