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Sounds like you'd be in climate where it would make a lot sense, you're basically running an air conditioner. Instead of the heat going outside it's going into the water. They cost about 1/2 to 1/3 standard electric hot water heater to run. Guess it depends on how you want to look at it but you are either getting free AC, or free hot water.
As I noted make sure it has option to use regular electric, you don't want to use the heat pump to heat the water when you're heating the house.
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With my current hot water I keep the temp on 120 and the mode set to low temperature.
I'd suggest bumping that up to 130, it really should be at 140. 120 is in the range that will promote bacterial growth. It's going to cost you more to bring cold water up to the higher temperature but it's about the same to maintain it. Use a mixing valve on the outlet of the tank to bring it down to 125
Consider what wartrace suggested, I wish I lived in area I could do this. It's really only hot enough for about three months a year here and my personal location is not very sunny because of trees.
You can build your own solar hot water heater pretty cheap. Since this is new construction you can carefully take this into consideration. If you set up a solar hot water heater below your electrically operated hot water heater you can use a thermosiphon loop to naturally circulate the hot water into the tank that it's generating.
You'd have the solar water heater outside next to wall with the hot water heater inside on the other side.
Here is a basic diagram how you would do it with solid fuel coal/wood stove, similar setup could be used for solar. Note there is two tanks in this diagram, that's not necessary but it will maximize the amount of hot water being produced by the thermosiphon. The trouble you run into with one tank is when you use water you're going to have cold water going into the tank. If the heater is on it's going to use electric to heat it up. With the secondary tank it's always going to be hot as it can be before it goes into the main tank.
There is only a very short coil about 2 feet long that is in the stove, it's a slow process but you can easily heat a 40 gallon tank overnight. I don't know what kind of time frame you're looking at for solar.
One last hing to note, there is two PRV valves listed on here, you only need one.
Sounds like you'd be in climate where it would make a lot sense, you're basically running an air conditioner. Instead of the heat going outside it's going into the water. They cost about 1/2 to 1/3 standard electric hot water heater to run. Guess it depends on how you want to look at it but you are either getting free AC, or free hot water.
As I noted make sure it has option to use regular electric, you don't want to use the heat pump to heat the water when you're heating the house.
I took a look at heat pump water heaters..hybrid ones that have electric as well.
They require air space of 1000 cubic feet which is a 10x10x10 room.
Most of the small home plans do not have an attached garage. My only choice would be the attic and I'm really not too keen on that idea.
Then again, I'm not set on a home plan yet so if I find one with an attached garage this certainly might be a viable option.
What I find amazing is the speed at which technology is changing.
Don't pay attention to what is going on in the industry for a year or two and you literally fall behind in what you would like to do.
I'm saving off this thread to my computer. Have a folder called "Future Home" and have lots of tidbits stored there for reference.
They require air space of 1000 cubic feet which is a 10x10x10 room.
They need a large air space becsue they are sucking the heat out of the room, if the space is too small the air temperature is going to drop a lot and the heat pump is going to work a lot harder. If you want to take full advantage of it you need it in a space you want cooled. Also note it acts as a dehumidifier too.
A possible alternative is putting it in a closet but you'd have to provide air circulation to it. If you had a louvered closet door off the main living space or other larger room that may actually work well enough with natural convection, you'd have to research it.
Putting it in the attic would vastly improve the hot water heating efficiency in the summer. You'll lose the benefit of the cooling and in the winter you're going to lose a lot efficiency. That is not a very good alternative.
If you live in Texas, I would certainly look at the heat pump water heater, installed in the garage. Here in Oregon it doesn't work as I would have to have a big mechanical room and the garage is not heated, but in Texas I would jump right on it.
I too am using an Air source heat pump and concrete floors, (Passive solar design) The kitchen where a lot of standing occurs will get a floor over the concrete.
...as I would have to have a big mechanical room and the garage is not heated,.
If you are sucking heat out of the room that you are using to heat the space you will use more energy and it will cost you more to run.
Consider this, to keep things simple suppose you have regular electric heat. If you put 3000 BTU's into the room the heat pump is going to use another 1000 to 1500 BTU's of electric to extract that heat from room air. It's simply more efficient to put the 3000 BTU's right into the water to begin with.
It's always going to be more efficient to heat the water directly with your primary heat source. The one exception if you are using a heat pump for heat, this gets complicated to calculate because of the variable nature of the efficiency of the heat pump but at some point when the temperature outside reaches X degrees it's going to start costing you more money and energy with them too.
Suppose your house heat pump is 200% efficient at 45 degrees. If your hot water heat pump is 200% efficient you're at $0 in savings for fuel costs over standard electric hot water heater.
These hot water heaters have a place epsecially in warmer climates, they may even be suitable for colder climates as long as you can use regular electric when it's no longer cost effective.
Last edited by thecoalman; 08-04-2015 at 06:35 PM..
These hot water heaters have a place epsecially in warmer climates, they may even be suitable for colder climates as long as you can use regular electric when it's no longer cost effective.
Which is precisely why I recommended it to the OP in Texas and it is not effective in my scenario.
Which is precisely why I recommended it to the OP in Texas and it is not effective in my scenario.
It's on my list to consider. I would need an attached garage though and not all the plans I've looked at have them. I'm downsizing to a much smaller home. A garage is not a requirement for me as I've never actually parked a vehicle in a garage..storage and projects area
You mentioned you had concrete floors and plan to put flooring in the kitchen.
I was going to go with polished, stained concrete myself until another poster pointed out that it was hard on the feet and might be an issue regarding getting older.
How is the concrete flooring working out for you ? Is the kitchen area the only area where you felt you needed the flooring over the concrete ?
This house sounds like a good idea. No matter how you heat of cool the structure above all keep it simple. As far as the concrete floors just wear shoes or slippers with thick shock absorbing soles and/or cushioned inserts. Drop down roll up shades can keep out a lot of solar heat. We use them on our south facing double sliding doors during the summer here in southern New Hampshire. All that glass can bring up the living room temperature by 30 degrees by 9 am on a cold mid winter day.
First, before you plant trees, look at where your water and sewage lines are to run before you plant. Many trees' roots will find these lines and creep into the pipes thus causing clogs. Good idea planning the home by the points on the compass. Not many consider this. In my case, I choose a lot in which my home's AC condenser unit was on the east side of the home. That way in the unit would be in the shade after noon. Having the unit in direct sunlight in the summer makes it work harder to cool the home. You should also consider what type of attic ventilation you want. Should you have a solar powered attic fan on a thermostat, should you have a ridge vent, should you have whirling golf ball vent fans that use no electricity, or some other options. Another thing to consider is location of the water heater. If you go with a tank water heater, you could conserve energy by having it located in the attic. The disadvantage of course is if there's a tank leak, you'll see it in the ceiling. When selecting your home's central air, don't skimp on the air ducts. To cut cost and make it easy to install, some home builders use lightly insulated flexible air ducts in the attic. Don't use them. If you can afford it, spend more money for sheet metal ducts with insulation wrapped around the outside of the ducts. These offer better air flow and better insulation. If you go ductless, don't buy by low price. Some of the negative reviews of ductless systems are because of cheaper systems installed, usually made in China. Consider a heat pump system with electric heating strips. If outside gets too cold for the heat pump to work, then the unit shuts off the compressor and turns on the electric heat strips. It takes less energy to run the compressor than to power electric heating strips. Install double insulated windows and don't forget UV protection. Having UV protection on the windows doesn't necessarily mean tinted windows. Some UV protection films are almost totally clear. No matter what AC system you install, sign up for a service contract with a reputable company to not only extend the life of the unit, but for it to run as efficiently as possible through it's service life. Another thing to consider is ceiling fans. When running, they use very little energy while making the home's occupants feel comfortable at higher temperature in summer and lower temperature in winter. Don't buy ceiling fans based upon physical appearance. Measure the square footage of the space the fans will serve and then look for fans of a particular size based on sizing charts for area square footage. To make the home energy efficient, you also have to consider the electronics and appliances. Select LED HDTVs (produce less heat), energy efficient refrigerator, get a toaster oven for small cooking without heating the home with the big oven, and automated external lights (like the garage or covered parking) that turn on after dark when motion is sensed and off after a set amount of minutes. Try using LED lights inside the home. Using LED bulbs outside the home might not work well since LED bulbs are effected by high temperatures. CFL bulbs will work well except for cold winter when the cold air will dim the light from the CFL bulbs.
We also like a north/south facing house and our last 2 in Florida have been like that. Great light all day long but not glare/heat of west sun. When designing your floor plan try and minimize/eliminate windows on the west side. Fast-growing trees are OK but also plant good ones at the same time, then you can cut down the fast growers (which might be invasive) and keep the quality shade trees.
We just bought a small rental property and it is north/south oriented with no windows on the west side at all (one bedroom on that side has a north window and the other has a south window). It's high summer here and no direct sunlight comes in to add heat, which surprised me because there is no roof overhang and no window shades installed yet. Summer sun goes high in the sky early so late afternoon sun is the problem. In the winter the sun's angle is lower so it might come in the south windows then but much less heat then, in fact the heat in winter may be wanted.
Make sure you build/buy with the thought of larger door openings for wheelchair/scooter access, maybe keeps you in your home longer. Also grab-bars in the bathroom and a wheelchair sized shower opening with no step blocking access. Try to get an attached garage or carport so your car stays cooler and you don't have to be in the rain/sun going to/from your house.
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