Installed a tankless water heater in Nov. and a woodstove in Feb.

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peakbagger

Minister of Fire
Jul 11, 2008
6,351
Northern NH
I must admit I am spoiled with my solar hot water system. I could not recommend someone doing one today as the upfront cost is steep but it does crank out the water with no muss or fuss.
 
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mar13

Feeling the Heat
Nov 5, 2018
428
California redwood coast
It's nice having an endless supply. My old tank finally gave out after 30 years. Takes a little longer to get to the tap though. You have to plan for it lol.
We almost switched from tank to tankless, but there would have been a lot of retrofitting required. Regarding length of time to get water through the tap, is that because the heat from the heat from the hot water sitting in the tank is not being conducted through the water & pipe outwards towards the tap?
 

peakbagger

Minister of Fire
Jul 11, 2008
6,351
Northern NH
The old way of installing hot water heaters in the basement was to run pipes straight up and then horizontal to a pipe going up through the floor. Heat would natrual rise up the pipe keeping the piping and the basement warm, then cooling down and dropping back to the tank. This happened 24/7 and cut down on heater efficiency but the water was warm up to the faucet. Folks figured that out and switched to heat traps on the outlet of the heater that stop this thermosyphoning or just put in loops of pipe on the outlet. That keeps the heat loss down but the trade off is it takes longer to get hot water. One company had a setup that would pump water from under the faucet back to the inlet of the hot water heater until the water under the sink got above set point. It saves heat but costs a bit to install. The other minor point is pipe size the hot water uses. There is less volume in a 1/2" pipe than a 3/4" pipe so a fixture fed from a half inch pipe will heat up quicker. One tip is to run a 3/4" pipe to the the shower and 1/2" pipes to all the other hot water uses. This reduces a drop in temp at the shower if someone else suddenly used water elsewhere.
 
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Solarguy3500

Member
Dec 3, 2020
140
Western MA
I must admit I am spoiled with my solar hot water system. I could not recommend someone doing one today as the upfront cost is steep but it does crank out the water with no muss or fuss.
^This.
I'm loving my new solar hot water system which is set up to pre heat the water before it goes into the existing electric water heater. We got it installed in November, so didn't get a lot of good production over the winter which I expected. But now, we're starting to get some good solar days and it's working great! In fact there have been a couple days where the electric water heater hasn't even cycled once. To illustrate, here is a screenshot from my consumption monitor on a cloudy day. Water heater usage is the light blue:
Screenshot_20210407-205359.png

The last couple days have been great solar days. Here's the last 24 hours:
Screenshot_20210407-205427.png

I agree on the upfront cost. When I got mine I caught the tail end of the MA solar hot water rebate and got $4,000 off and was able to finance the remainder using the Mass Save 0% interest HEAT loan. I'll also be getting a check for $2,000 for Alternative Energy Credits in the next few months. The MA rebate program ended at the end of 2020 and if I hadn't been able to get the rebate, I probably would not have done it.
 
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