View Full Version : Water heater

08-29-2016, 07:39 AM
The new house needs a water heater. We are going propane. Because of the location, I have to have a direct vent or powervent heater. So, cost wise this really drives the price up.

This opens a new option, and one that bth plumbers I spoke with are advising, a tankless. Cost is basically the same as a good direct vent. The issue is, direct vent uses no electricity but the tank needs it. I feel like the tank is a better choice.

Can anyone shed any light on this for me? I know we would have to have a generator running for other items, but if the power was out, the tank would give us 50 gallons of water and heat without power. The tankless saves propane in a big way.

Also, I have read of issues with the tankless in terms of a "cold water sandwich " and other short use issues like washing hands, dishes with water going on and off, etc.

I do like the idea of the space requirements for the tankless. It really would help open up the basement bathroom and make it more useable.


08-29-2016, 07:42 AM
Along the same lines, we have to do a full replumb of the house eventually. Water here is tough on copper. So, pex or pvc? I really like pex, but repairs or changes require special tools, I am leaning toward pvc, but flexible pex would be 100x easier to get into a retrofit area.

08-29-2016, 09:40 AM
Along the same lines, we have to do a full replumb of the house eventually. Water here is tough on copper. So, pex or pvc? I really like pex, but repairs or changes require special tools, I am leaning toward pvc, but flexible pex would be 100x easier to get into a retrofit area.
Of the choices, my vote is for pex, specifically pex-a. If you're working with it for the first time, get some extra and make yourself a test fitting you can practice the connections with.
Stick/compression fittings are expensive but are useful if your going to use a header.

08-29-2016, 03:29 PM
The tankless are great but like anything , your right the drawback is shut it off for a split second an the fire goes out with no flow . So don't turn it off completely I think even a slight flow will keep the fire going then go back to high flow , like washing hands or even a shower , dam cold water hitting you is a bitch lol , it just takes a little learning curve . It takes very little E-power to run , only the vent fan and igniter .

08-29-2016, 04:53 PM
Have you looked into solar? Hooked in with the system they can save $

08-29-2016, 08:00 PM
I have, but we are not there yet. That will have to wait.

08-29-2016, 10:57 PM
redman, first off, i vote NOT PVC. Regardless of the PEX, it will be much easier to deal with. If SHTF, pex requires mechanical tools only. No glues/primers that might dry up on you PLUS PEX will give under stress. Its not brittle like PVC. It might be more expensive but IMO its worth dealing with. Also, i've seen PEX freeze up completely and not bust. If SHTF and you dont keep your pipes north of 32 you're gonna want PEX.

Regarding the water heater, you are correct in your worry about low flow situations. I think they've improved but i havent kept up with those specs. From an efficiency standpoint i would hands down say tankless (condensing, of course). However, given that you are on here I would say only go tankless if you have a PV system/back up power source. The moment you lose power your powered vent is down making your tankless a relic. In addition, if you are at all worried about EMP... tankless have electronics in them. Something else to consider.

Keep an open mind about heating. Going tankless doesnt mean you cant have a storage tank to address any low-flow issues you might encounter. However, at the end of the day, unless you are installing a PV system i would go TANK.
1) no moving parts, no fan, no electronics (beauty in simplicity)
2) propane is cheap right now and it also stores near indefinetly so you can get a big propane tank. Gas for a generator has a shorter life.
3) having a tank means having storage of h/w. You can adapt a solar collector to this and put a circulation pump on it down the road. with tankless, you'll have to find a storage vessel.
4) hard water will have a much quicker negative effect on tankless than a tank (life span but more importantly, efficiency... which is why you are looking at it to begin with)
if you have hard water, plan on stockpiling salt. Otherwise, plan on having hard water when you make your final decision.

Also to consider:
a tank is about 50-80kbtus depending on size. A tankless will easily run you 180kbtus most being around 200kbtus (last time i looked). I'm not familiar with sizing lines for propane but given a 3x difference in fuel consumption that will have to be considered when plumbing for either. You might save a little money going with a tank. (i know, it would likely be negligible at best)

If you read all that and are still thinking tankless then you will probably know there are two types. Condensing and non-condensing. Non-condensing for prepping is worthless. You'll only get about ~80% efficiency while getting all the 'cons' of a tankless (moving parts and electronics). Condensing are great b/c their efficiencies are 90-95% BUT the heat exchanger to condense the combustion gas must be maintained, in addition to the rest of the appliance, and its an expensive sucker to replace. You will pay much more for the condensing type. If you haven't researched it yet you might be surprised at how much more the condensing type cost.

Sorry for the long post. Hopefully this information will help.

08-29-2016, 11:08 PM
Have you looked into solar? Hooked in with the system they can save $

Correct. In fact, I've read and heard multiple times that solar thermal is the best bang for buck, compared to PV, since your w/h consumes the most energy of any appliance right after a/c. You can collect more thermal energy than you can convert to electricity.

08-31-2016, 09:10 PM
A solar hot water system, like a tank, is something you can drain if water becomes a vital topic.

02-18-2017, 05:34 PM
PEX is the way to go. As far as heating water, you can also run generators on propane so you would ahve both power and hot water. One thing to consider, if you are on a well for water, hard water or other minerals.

Kailani Kealoha
02-19-2017, 03:27 AM
If you live in a sunny area, you should check this out.


They cut down on water heater usage pretty dramatically.

02-20-2017, 10:23 PM
We've been discussing the possibilities at my house for a while.

07-20-2017, 05:53 PM
As usual, I'm late to the party, but here's my $.02 worth. About 8 years ago we went propane tankless to replace our old 30 gallon tank. Initial cost was painfully high, but it has cut our propane bill in half. We were buying 150 gallons of propane twice a year. Now we buy 150 gallons once a year, and that takes care of all our hot water and cooking needs. We use wood to heat the house, so the only time we use the propane furnace is on cold mornings when it will warm up quickly during the day.

The initial drawback was the need for electricity to operate the tankless. As someone else stated, it doesn't take much to run the igniter and blower, so I opted to put a couple of solar panels on the roof to charge a couple of AGM 12v batteries in the garage. With a small solar controller and a 600w inverter, we now have hot water regardless of power outages. The first winter I ran this setup, I discovered the tankless heater uses electricity to heat the pipes inside the box when the air temp drops below 38 degrees. That emptied my batteries pretty quick. Therefore now I unplug the tankless on cold nights and leave the water dripping in the house to keep it from freezing. Also put an oil lamp on the floor under the tankless just to make sure. Here in Texas we seldom get prolonged below-freezing temps, so that should keep us going.

07-20-2017, 06:07 PM
I think I posted this here, but if not...
We have been very happy with the water heater. I am not happy with electricity for the starter, but such is life.

The stove and the water heater are propane. I would guess we will use about 200 gallons per year with three of us. We also cook a pretty good bit.

The ac heater we went with a diakin whole house. Wow. That is amazing this summer. $75 electric bill for ac, 2 freezers, fridge, dryer washer, etc. We are thrilled. We will still heat with wood as much as we can, but this should help end the 4 am stokings. That will be huge with a baby on the way.

Now I need to get going on our addition of the new kitchen and fix up the rest of the fixer upper. Slower going than I had hoped. 70 plus hours a week at work has something to do with that.