The Tank › Hot Water Tank-Propane or Electric
- April 9, 2008 at 6:45 am #8568sloopy312Participant
I’m glad I came across your site. We are building our first new home. Since I am disabled and up in years I want something trouble free and safe. Our home will be up in forest land with only electric supply.
I am thinking about installing a vented propane fireplace for looks and heating if we loose our electricity which I am told happens up there. We will also have a wood stove for back-up heat and cooking.
So, should I buy an electric or propane water heater? If propane, what size propane tank-we will live about 20 miles from the closest propane place. Or should I buy a portable tank that I can lift myself? There is only two of us but we will have two stories with a bathroom in each. As a side note the electric water heater in our present home leaked twice spilling water all over our floor. Is there a way I can make sure this won’t happen in our new home?
Also from reading your other articles I am assuming that our hot water tank should be 40 gallons. Is that correct?
Nelson, Retired USAFApril 9, 2008 at 9:07 pm #8578Larry WeingartenParticipant
Hello: Answers to your questions could fill a book 🙂 I’m going to start by suggesting you look into SIPS or foam core panels for the structure of your new place. That gets you closer to having an efficient house. Then look into manifold or home run plumbing. This is a technique of using small diameter tubes to deliver water to the taps quickly so there is less waste. If the plumbing is distributed widely around the house, do a search for “Gary Klein structured plumbing” and see what you learn.
I’d probably use a direct vent propane heater. An efficient home needs care taken to keep the indoor air clean. As to propane tank sizing, call the local suppliers and see what choices are. Personally a two hundred gallon tank lasts me ten months, but I know folks who use more than that in one month. Carrying small propane cylinders around doesn’t sound like much fun. If you own your tank, you can shop around for the best propane price. As for water heater sizing, best is if the volume of the tank gets used daily. Thirty gallon tanks often cost more than forty because forty is the most common size. Get one with the highest EF number you can find. If you’re going to put in a tub, make sure the heater can serve it. Warranty is not too important as long as you can add a second anode or replace the existing one easily. Do leave adequate overhead clearance (3-4 feet), or wish you had 😛 Put the tank where it’s leaking won’t cause damage.
If the upstairs has a shower that will get a lot of use, consider putting in a GFX shower heat exchanger 😎 And that was only the books’ introduction!
Yours, LarryApril 10, 2008 at 6:46 pm #8583energyexpertParticipant
First, thank you for your military service to our country.
Gas water heaters have EF (energy factor) ranges of 0.5 to 0.98 (http://www.navienamerica.com). Compare gas with an electric WH with EF of 0.91. If propane is $3/gallon the breakeven cost of electricity is $0.104/kWh for the gas WH with EF of 0.98. Breakeven cost of electricity is $0.204/kWh for the gas WH with EF of 0.5.
If you are to be back in the woods, will you have a well? Power outages and a well usually suggest a generator. The smallest generator you can use is better than bigger. A 15 kva unit will use less fuel at full load than a 40 kva will running unloaded. If you run it off of propane then you have a fixed and limited fuel supply assuming bad weather caused the power loss and the propane truck can’t get to you for a week.
A Marathon WH is fiberglass so cannot rust and therefore should never leak. (It is always good to put a WH in a pan with the pan drain routed to a place to accept water.) Buy at http://www.chec.coop. But during a power outage it is a waste of fuel to make electric resistance heat (eg electric WH). A generator is only about 25% thermally efficient. If you make electric hot water from a generator you have to burn four gallons of propane to get one gallon of propane worth of heat into the water.
As Larry said, volumes can be written about the options available when building a new house.
DavidApril 11, 2008 at 4:40 am #8585sloopy312Participant
Larry and David thank you for your advice. I’ll show it to our contractor.
I should have mentioned that we will have a well. And we will also have an electric generator in case the power goes out. We will use the generator to give us light power, enough to run our water well pump, and maybe to run a two burner hot plate unless we use the top of our wood stove-assuming we put one in. We have 21 acres of trees so firewood will be no problem.
Any added advice will be gladly accepted. I’m not too smart at understanding some of the technical terms however.
I may settle for an electric 40 gallon water heater and a propane fireplace that has an underground 250 gallon tank-but all this is up in the air as I want to digest your information.
Again thanksApril 11, 2008 at 8:56 am #8586energyexpertParticipant
Generators today usually have two ratings: one for continous load and then a surge rating. A 7500 watt generator might be able to surge to 13000 watts for starting a motor (well pump). Many plumbers will oversize the pumps; I don’t know why. The house I built had a 2 hp well pump. When I installed a geothermal heat pump, the well pump cycled way too much. When lightning took it out I replaced it with a 1/3 hp pump and set the geothermal water flow and well pressure switch such that when the geothermal unit was running the well pump never shut off. But I had a high water table and only had to lift the water about 20 feet.
Your generator will need a surge rating of at least 5 times the maximum running load the generator will pull. A 2 hp motor would need a generator surge of 10 kW while a 1/3 hp motor could get by on a 2 kW generator.
Brayden Automation (http://www.brayden.com) sells a demand controller which will work with a generator to limit the loads imposed on the generator. Thus, a relatively small generator can be connected to the whole house panel so you can power anything (but not everything at one time) rather than just having the generator power a subpanel with only certain circuits having power during the outage.
DavidApril 14, 2008 at 2:01 pm #8596Larry WeingartenParticipant
Hello: Affordable Comfort just had their big yearly conference http://www.affordablecomfort.org/ 😕 There are other events coming up and both you and your contractor would benefit by attending. Much of the rest of “the book” is there 😉 I can promise you that whatever investment in time and money you make with ACI, it’ll repay itself many times over.
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