Thanks to you and others who responded so quickly..

I'll follow this guidance.


"Tom" wrote in message
news:0ddqf.43760$eI5.17163@trnddc05...

"Bettina" wrote in message
news:Eycqf.1288$0u5.665@trnddc01...
We live in a six-unit apartment building, and all units are served by a
single water heater.

Last month we had a sudden increase -- about 25 percent -- in gas usage.
Emphasize, USAGE, not price -- which also increased.

The water heater is around 10 years old. Do such heaters lose efficiency
with age?

There is no other gas appliance on this meter.

Any guidance or suggestions welcome.
Certainly they become less efficient as scale builds up inside but not
suddenly. I would look for a leak somewhere in the hot water line.
Perhaps one of the apartments has a dripping faucet or a hot water line
may have broken if it runs under the concrete slab where it wouldn't be
immediately noticeable. Have all apartments turn all water off and then
check the water meter. If it is still turning, turn off the water to the
water heater and see if the meter still turns. I had a hot water line
break under the foundation once and in addition to a big jump in
electricity usage (electric water heater), I also had about a 30,000 gal.
jump in water usage for that month. Of course, there's always the
possibility that one of the tenants has started offering hot showers to
the homeless. Or even, maybe your utility company simply estimated last
months bill instead of actually reading the meter.

Tom G.