Replies

1. 
   josh_jones | Jan 01, 2022 09:05pm | #1

   I think it depends on relative energy cost and availability. Demand (I assume you mean tankless) generally require quite a bit of instantaneous energy but are efficient because they only use energy while hot water is demanded. From what I remember - electric demand heaters get pretty ridiculous with their electrical requirements (over 100A depending on how much flow you need). Not sure about gas flow requirements for propane. If you go with a tank style unit, I'd consider a heat pump unit. We've had one for a few years now and I have yet to exhaust its capacity.

1. 
   EhvC | Jan 01, 2022 09:19pm | #2

   Thanks Josh, you have a geothermal heatpump with the hot water option?

1. 
   josh_jones | Jan 01, 2022 09:24pm | #3

   Nope - air source. Rheem 50 gallon. It can also do electric only or high-demand (electric + heat pump).

2. 
   josh_jones | Jan 01, 2022 10:46pm | #4

   EhvC - I just happened to find this article - the unit described is the same make as mine (i think it's a bigger unit than mine, though). https://www.greenbuildingadvisor.com/article/living-with-a-heat-pump-water-heater

2. 
   paul_wiedefeld | Jan 02, 2022 11:39am | #5

   Propane and electric resistance are probably similar operating cost wise. If you want the most efficient option, then heat pump. Either way, a tank is better, tankless comes with many compromises. Reducing demand (low flow shower heads) and a drain water heat recovery pipe both cheaply and reliably save energy and add capacity.

1. 
   josh_jones | Jan 02, 2022 12:20pm | #6

   I agree - a tank, especially when heated by heat pump - is the way to go. I'm not sure if it helps with efficiency, but I also added a thermostatic mixing valve and cranked the tank temp to 140 degrees. The mixing valve mixes in cold water and brings the temp down to whatever you set it to (in my case 125 degrees). This definitely expands capacity. Even doing several hot water tasks simultaneously (showers, dishwasher, clothes washing, etc) I have yet to run out of hot water. Doing this also allows you to use hotter water for appliances and regulate sink and shower water down to safe levels.

   At the end of the day - all I know is my electric bill went down noticeably once I installed my heat pump water heater.

2. 
   EhvC | Jan 02, 2022 01:24pm | #7

   Thanks. Makes sense

3. 
   artisanfarms | Jan 02, 2022 05:02pm | #8

   One of my son's installed an air source heat pump water heater last year. There are two people in the house and they always have sufficient hot water. The water heater is also noticeably cheaper to run than the propane heater they replaced.

4. 
   dan_saa | Jan 03, 2022 01:10pm | #9

   I like to have a tank for emergency water supply. More of a concern in California with earthquakes.

1. 
   josh_jones | Jan 03, 2022 01:33pm | #11

   Good point. Unintended benefit for me - being that I also live in a seismic area (Western Washington).

5. GBA Editor
   Kiley Jacques | Jan 03, 2022 01:26pm | #10

   I recommend you join us on the BS* + Beer Show this Thursday at 6PM ET. Allison Bailes will be talking about residential hot water distribution systems and is bound to talk about water heaters. You can also ask for his opinion directly from the chat box. (Use this link to register--it's free.)