351–360 of 406 posts
When I needed a new air conditioner a couple years ago I was quoted $17,000 for a heat pump. I can only guess at that point whatever energy cost savings it would bring would never be realized within the service life of the system. I went with a $6000 standard replacement AC unit.
When I needed a new air conditioner a couple years ago I was quoted $17,000 for a heat pump. I can only guess at that point whatever energy cost savings it would bring would never be realized within the service life of the system. I went with a $6000 standard replacement AC unit.
What size? The last split system I bought cost about AU$1600 installed ( ~$1060) for 3.5kW... Looking at prices now, even going up to a ducted 14kW Mitsubishi Electric heat pump/AC is only AU$5000 (before installation, and you would need to add ducts and vents etc. - that's just the controller, outdoor unit and in-ceiling unit, but still)... Is this in the US? Maybe the market is distorted just because not enough peo…
Earlier quoted context omitted.
I have new heat pumps in a very old, under insulated, and leaky house. I didn't use my oil furnace last winter (the first since two additional pumps). My costs were about half of the previous year, and I'm sure my carbon footprint was much better as well. Can you say more about what your comment is supposed to mean?
Our house (in Europe) is relatively old and not well insulated by modern standards, and all of the advice we read and receive from experts is that heat pumps are not a good fit without additional insulation. The gist is that we’d need to spec larger units and/or run them harder than usual, removing savings vs. gas.
A worked example - In AU gas is metered per MJ - 3.6MJ/kWh. So 3c/MJ means that gas is equivalent to electric heat at 12c/kWh. Heat pump multiplies that by roughly 4x, so 48c/kWh is the Breakeven point for a heat pump vs gas heating.
Heat is heat, it makes no difference. insulation would save you money on all heat sources though, and can be a pretty cheap upgrade (insulating the roof space, for example).
Earlier quoted context omitted.
I've seen heat-pump base water heaters, but never a clothes drier. That sounds interesting. Now I have something new to research, thanks! Personally, I'm always curious why there isn't a more unified heat-exchanger system built into the structure of a house. HVAC, Water, Refrigerator, they all need to move heat from one place to another, why not work together?
I've tried to make the idea work in my head many times but my conclusion has been that I don't think there's quite enough co-incident demand for heating and cooling in the average house. For example, yes, I could generate all my domestic hot water from heat from air conditioning in summer, but in winter I need to be able to generate it plus heat the house, so I need enough capacity to generate that heat from the outs…
This enables your hot water heater to use the same circuit to heat water - that decreases your hot water bill to around a third, even in winter as the necessary heat isn’t taken from the indoor air but from the ground.
Heat pumps are great, but it’s the dc inverter and advances in compressor efficiency that is really the biggy on energy usage here. Every one of these “heat pumps are the future” articles is so soft on data, and they often fail to explain the basics or a simple “why.” Once we get past the clickbait heat pump articles, we can actually make an impact.
Plus, they can run on any power source, including green and/or decarbonized.
In India, we have been using "Ductless Air-Source Heat Pumps" aka split AC units with 3,4,5 star energy ratings for decades. The more efficient ones come with dual inverter compressor which allows them to operate at lesser power (for lesser cooling) during long continuous operation periods (like sleeping at night).
Earlier quoted context omitted.
I have new heat pumps in a very old, under insulated, and leaky house. I didn't use my oil furnace last winter (the first since two additional pumps). My costs were about half of the previous year, and I'm sure my carbon footprint was much better as well. Can you say more about what your comment is supposed to mean?
Our house (in Europe) is relatively old and not well insulated by modern standards, and all of the advice we read and receive from experts is that heat pumps are not a good fit without additional insulation. The gist is that we’d need to spec larger units and/or run them harder than usual, removing savings vs. gas.
We can assume that you currently have a high power (e.g. 28kW+) gas heater and radiators that can only emit that kind of power at high water temperatures. This system works in tandem (place where has is burnt and devices that emit the heat throughout the house). A leaky house typically needs a higher heating power in the interest of comfort: it'll have a higher power loss, and you'll want to not spend days bringing it up to room temperature in case the power was out or what not. These heating systems are usually overdimensioned, so any variability in the power loss of the house is compensated for by simply upping the power output.
A heatpump is lower power, and therefore slower, and therefore you'll want to limit the heat loss of the house, because when things go wrong (somebody left a window open in winter), you're gonna have to wait some time before the pump's caught up. Calculating a building specific optimal heat pump power is already trickier, and it's trickyness is increased without that insulation.
Which doesn't meant that you cannot do it yourself! You can simply accept that response times are going to be slower (so, if you flip the temp up from 17C to 20C that it's gonna take half a day). Best is to just set it to a temp and leave it there, it's no longer the advantage it was to modulate.
Most important is to not underdimension the heat pump. I've never seen a salesperson offer it, but there's online communities of people who can and do calculate it for older houses (gas consumption is a good proxy). One thing to understand is that heat generator power (be it a heat pump, gas heater, whatever) needs to match the heat emission power of the system that releases the heat (radiators and floor heating most likely). The water is gonna run at lower temps with a heat pump, so that means that your radiators will emit less heat, and probably not enough. You need to make sure that at the water temp the pump outputs economically the power output of the delivery system matches. This usually means putting in floor heating and/or significantly larger and more efficient radiators.
Heat pumps are great, but it’s the dc inverter and advances in compressor efficiency that is really the biggy on energy usage here. Every one of these “heat pumps are the future” articles is so soft on data, and they often fail to explain the basics or a simple “why.” Once we get past the clickbait heat pump articles, we can actually make an impact.
I think many people suddenly realized that moving heat translates to efficiencies far north of 100%, also for heating. Moving in opposition to creating heat, which tops out at 100% in the best case. Plus, they can run on any power source, including green and/or decarbonized.
They're quite popular in the Netherlands due to high natural gas prices (since the Ukraine war) and two types of government subsidies. One is a direct subsidy on buying a heat pump device, the other is based on our energy pricing.
Basically you can offset all energy-taxes across the year with solar production. Everything you over-produce in summer carries over to the winter. So if I assume for example that my solar system is written off in 10 years to zero (reality is probably better than that) my total energy cost per kWh is only 7 cents all year round.
A pretty low capacity heat pump is able to provide 90% of the heating and cooling of a normal house. They're combined here with gas based systems to cover for the few days a year that it's exceptionally cold or when you need more hot water than the heat pump could deliver. That means you can buy a much smaller capacity (cheaper) heat pump.
If you compare the running cost of heating at only 7 cents per kWh with a heat pump to natural gas prices "pre Ukraine" it'a already roughly about 4 to 5x cheaper. Now with gas prices nearly doubled you're looking at a 8x cost saving with a heath pump vs using natural gas. The only hurdle is that you need to buy and install a heat pump device, so it takes some time to make that back.
The government is planning to slowly reduce the energy-tax offset from 2025 to 2031. But even without that it's expected that the move from gas to heat pumps will continue.
Earlier quoted context omitted.
An A/C is a heat pump. Stop trying to change existing terminology
I've only ever known the term "heat pump", in the context of HVAC, to mean "an air conditioner that can also be used to heat".
https://www.iea.org/reports/the-future-of-heat-pumps/how-a-h...
or a simpler article https://en.wikipedia.org/wiki/Heat_pump
It is different from a radiator or a furnace.
Swamp coolers are massively underutilized as well. The vast majority of residential cooling in all but the most humid climates can be done with nothing but a fan and some cold water; no compressed gases necessary.