Heat pumps

Suns

My home furnace and water heater (gas) are getting near 20 years old and I'm exploring alternatives. I've seen mention here of heat pumps and water heater heat pumps. Are there units that combine house heating/cooling with water heating? Are these units a large production to install?

peakbagger

Re: Heat pumps

We need more info, where do you live?. In moderate heating demand areas air sourced heat pumps are a good solution. Most systems requires ductwork and frequently the duct work was run outside of conditioned spaces which can lead to high energy loss. A modern installation done correctly can reduce this loss. For colder weather areas ground source heat pumps make more sense.

The trade off is that the front end cost of properly installed heat pumps, especially ground sourced ones is usually a shock compared to replacing a furnace.

There are options to get hot water off a heat pump, but I expect that the new heat pump hot water heaters are probably a better alternative.

One thing to consider is if your furnace is still in good condition is to keep it for cold weather and install a couple of air sourced mini splits. They work well down to about 10 degrees F and are super efficient.

One other thing to consider is that if you have an older home with a small electrical panel (60 or 100 amp), you may need to upgrade to a 200 amp panel if you install a conventional heat pump.

waynefromnscanada

Re: Heat pumps

peakbagger wrote: »

One thing to consider is if your furnace is still in good condition is to keep it for cold weather and install a couple of air sourced mini splits. They work well down to about 10 degrees F and are super efficient.

Agree. Here in Nova Scotia this morning, the temp is down to minus 21C, which is considerably below the temp required for efficient air source heat pumps and we are glad to have the furnace. On not so cold days however, the mini-split far outshines the furnace in cost per BTU.
Another thing to consider is the effects of the heat pump water heaters that look more or less like a traditional electric hot water tank with a compressor mounted on top. These do a great job of cheaply heating water, but they turn the area in which they are installed, into a refrigerator as they suck warmth out of the air to hear the water. Learned from a local building supply center that in this area, the problem is sever enough that people are installing duct work to bring in outside air to feed the heat pump, then expel the chilled air back outside. Kills efficiency in cold weather.

solar_dave

Re: Heat pumps

But in a place like the southern USA air sourced heat pumps do very well for both space and water heating. Ground sourced heat pumps are very efficient but also very expensive in comparison.

We have been running ours pretty consistently at night lately with lows around 45F and with our TOU plan not allowing on peak power to offset off peak power our electric bill was only $28 in November. That includes all our usage including charging the Chevy Volts. It was a bit higher in December.

Suns

Re: Heat pumps

I am in the Seattle, WA area. Temperatures range from 0 to 100, but the vast majority of days are 40-80 degrees F.

I was reading some Amazon reviews of the Geospring and it doesn't sound like a very reliable unit. Are there better ways to go?

peakbagger wrote: »

We need more info, where do you live?. In moderate heating demand areas air sourced heat pumps are a good solution. Most systems requires ductwork and frequently the duct work was run outside of conditioned spaces which can lead to high energy loss. A modern installation done correctly can reduce this loss. For colder weather areas ground source heat pumps make more sense.

The trade off is that the front end cost of properly installed heat pumps, especially ground sourced ones is usually a shock compared to replacing a furnace.

There are options to get hot water off a heat pump, but I expect that the new heat pump hot water heaters are probably a better alternative.

One thing to consider is if your furnace is still in good condition is to keep it for cold weather and install a couple of air sourced mini splits. They work well down to about 10 degrees F and are super efficient.

One other thing to consider is that if you have an older home with a small electrical panel (60 or 100 amp), you may need to upgrade to a 200 amp panel if you install a conventional heat pump.

Blackcherry04

Re: Heat pumps

I have a little different twist on my Air/Air Heat Pump. I have a hydronic coil in the duct that is energized @ 26 deg outside temp. I have duct thermostats that regulate the duct air temperature to 88-89 degrees via the circulator pump. The coil is a closed loop off two 30 gallon hot water heaters, one electric and one gas @ 140 deg that I can switch to either or both. As the heat Pump heat output drops off they will pick up the load and works well down to 5 or so degrees where I figure the gas furnace can take over and has a better bang for the buck for 5 or so days a year we are below that. You'd be surprised how much heat is in 60 gallons of hot water and how little they cycle for what you get.

Rybren

Re: Heat pumps

I had an air-sourced heat pump in one of my previous homes. It would provide adequate heating down to about -15C. Once the temp dropped below -15C, the furnace would kick on. I really don't know how energy efficient the heat pump was, but my energy bills were the lowest of any place I've ever lived. (Everything was powered electricity and the city had a sweetheart deal with the Hydro-electric utility that ran the generating station on the edge of the city)

Skippy

Re: Heat pumps

Suns wrote: »

My home furnace and water heater (gas) are getting near 20 years old and I'm exploring alternatives. I've seen mention here of heat pumps and water heater heat pumps. Are there units that combine house heating/cooling with water heating? Are these units a large production to install?

From my experience, the size of the heat pump INCLUDES the output of the desuperheater (fancy name for the water heater portion) so even though I have a desuperheater on my heat pump, I did not connect a water pump and hook it up. Instead, I went out a picked up a apricus high efficient solar water heater, as a pre heater for my on demand water heater. . . I can only say that my 3 ton water to water heat pump heats up 100 gallons of water for my radiant floor heating really good.

there are different models : air to air, air to water, water to air, water to water . . that's just the heat pump to do the heating, add a desuperheater to any of those, and you have hot water. . .

Cheap to run, and very reliable. Efficiency wise, I believe that heat pumps are rated at something like 300 percent efficient. . first you run 1 kw of power thru it. . . so you get 1 kw worth (roughly) of heat energy generated by the machine itself running (thats still goes into the house- no chimeny) next, since the machine is running, - for me having a ground source heat pump, you get 2 kw worth of heat out of the ground - so I have been told for every 1 kw of energy, I get 3 kw of heat. . correct me if I am wrong, but that is what the guy who sold me the thing told me, and my heat bill shows it.

As for the forums, and solar, I cannot run my 3 ton heat pump off solar. . I did hook it up to my 100 amp house power, (30 amp dual pole breaker) as well as the on demand water heater (dual pole 60 amp breaker - I think), and no, I cannot do a load of laundry while the heat pump is running and I am taking a shower . . oh darn. . .

Just my thoughts.