Simple Water Heater Emergency Heat

This year’s Halloween nor’easter has started me thinking about how to heat my apartment if the power goes out for an extended period of time.

If the water and gas are still on, one possibility is to make a simple hydronic heating system using the water heater. The basic idea is to hook a hose to the hot water faucet, run it around a room, then to a drain.

As a proof of concept I picked up a faucet to garden hose adapter and some extra hose from Home Depot. After setting up the system I turned off the furnace and went to sleep.

Table of Results

Time Room °F Flow Rate GPM °F in °F out BTUs Notes
10:00 pm 70.1 0.5 150 100 12,500 Max. flow water heater can sustain
10:23 pm 76.8 0.2 150 100 5,000 Reduced flow
10:27 pm 77.4 0.2 150 95 5,500
10:57 pm 79.3 0.2 150 95 5,500 Too hot, opened window and door
11:19 pm 77.5 0.1 150 90 3,000 Reduced flow, closed window and door
04:30 am 75.9 0.1 145 85 3,000

The system worked extremely well. I suspect it could easily heat two rooms.

Setup Details

Procure a dual thread for 3/4 inch hose or male 55/64 inch adapter, model number 37.0109.98, $5.95. Alternatively the hose could be attached directly to the washing machine faucet.

Attach adapter to hot water faucet

Attach adapter to hot water faucet. Connect hose to adapter

Spread hose around the room

Spread hose around the room

Ensure there are no kinks

Ensure there are no kinks

Drain waste water into tub

Drain waste water into tub



  1. I like this idea quite a lot, though I don’t like that the water is lost/wasted. Our water heaters are sitting there keeping water hot even when we don’t need it. Is it possible that the hose system could be routed back to join in with the incoming feed to the water heater? Then we’d have a closed system that doesn’t waste water.

    • Hi Darrell, that is possible but would require a pump to circulate the water. In my view using water to heat your home in an emergency is no different than using kerosene to run a heater. The flow rate I ran overnight provides eight hours of heat for only 48 gallons of water, less than what is used for a 20 minute shower.

  2. Hey Paul, don’t know if you’ll even see this given the age of the post, but if you do can I have permission to post this to my site? I’d give credit and link back to the original, of course.

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