* REDUCING HOME UTILITY COSTS AND CARBON - Water Heaters
Typical storage water heater.
Water heaters are a major contributor to greenhouse gasses and your utility bill, so they are a good easy target for saving money and reducing carbon. Most residential water heaters are electric or gas-fired storage units, with electric being much more common. The problem is higher than necessary set temperature and 24/7 operation when hot water is needed only a few hours a day.
If your heater is less than 10 years old and in good working condition replacement is probably not a good idea. However, if you decide to replace it, a later posting will explore replacement options for saving money and carbon.
So let’s assume you are going to work with the heater you have for now, and that it is either an electric or gas-fired storage heater like that pictured. The table below shows four cost and carbon reducing step you can take on either heater type. Collectively, these steps can cut cost, energy and carbon by up to about 45% and all for the price of a simple timer. Your values may differ a little from these, but several sources list similar numbers, including direct measurements on a gas heater.
If your heater is less than 10 years old and in good working condition replacement is probably not a good idea. However, if you decide to replace it, a later posting will explore replacement options for saving money and carbon.
So let’s assume you are going to work with the heater you have for now, and that it is either an electric or gas-fired storage heater like that pictured. The table below shows four cost and carbon reducing step you can take on either heater type. Collectively, these steps can cut cost, energy and carbon by up to about 45% and all for the price of a simple timer. Your values may differ a little from these, but several sources list similar numbers, including direct measurements on a gas heater.
SIMPLE CHANGES TO REDUCE CARBON AND COST
The biggest and easiest gains are from reducing the set temperature if it is higher than necessary (many are set to 140 by default because of archaic dishwasher guidelines), and using a timer to turn the heater off when not needed. You may wonder about the high total energy use for an electric heater, but the problem is the 70% loss in energy from the power plant fuel supply to electricity at the heater. This loss component is ignored by many sources, thus portraying electric heaters as much more carbon friendly than they are.
Carbon, cost and total energy for several gas
and electric water heater operating conditions.
Operating conditions for table at left.
A. Operating at 140F for 24 hours/day
B. Operating at 120F for 24 hours/day
C. Operating at 120F for 16 hours/day - off 8 ours at night
D. Operating at 120 F for 16 hours weekends, 10 hours weekdays
E. Turned off for two weeks of vacation per year
A. Operating at 140F for 24 hours/day
B. Operating at 120F for 24 hours/day
C. Operating at 120F for 16 hours/day - off 8 ours at night
D. Operating at 120 F for 16 hours weekends, 10 hours weekdays
E. Turned off for two weeks of vacation per year
Both types of heater show good savings for these changes, but the gas-fired unit offer less than half the carbon and operating cost of an electric unit. All that is needed is a simple timer to shut the heater down when hot water is not needed.
TIMERS FOR ELECTRIC WATER HEATERS
Typical electric water heater timer.
Timers for electric heaters run about $60 for a simple mechanical unit like that shown. This unit will provide the same set of on-off schedules every day. Cost for a digital timer which gives more day to day scheduling flexibility is about $80. Both will have a manual override to get hot water off schedule.
Links 1 and 2 are to videos covering timer installation, but they are not very well done. Given this, a good written installation guide is provided in Link 3. Expect payback for the cost of a DIY timer in a few months, a bit longer if installed by an electrician, but still very cost effective.
Link 1: youtube.com/watch?v=2Tym7jmNtk8
Link 2: to be added
Link 3: waterheatertimer.org/How-to-wire-WH40.html
Links 1 and 2 are to videos covering timer installation, but they are not very well done. Given this, a good written installation guide is provided in Link 3. Expect payback for the cost of a DIY timer in a few months, a bit longer if installed by an electrician, but still very cost effective.
Link 1: youtube.com/watch?v=2Tym7jmNtk8
Link 2: to be added
Link 3: waterheatertimer.org/How-to-wire-WH40.html
TIMERS FOR GAS WATER HEATERS
For gas-fired heaters that need a variable schedule day to day over a week, the $16 dewenwils timer shown in the left photo below or a similar unit is a good choice. If every day can have the same timing schedule then the simple $6 timer shown in the right photo will suffice. Both timers are very easy to use, trouble free and have manual overrides to provide hot water when the timer is off.
Checking with your utility and/or the manufacturer to make sure your particular heater will work well with a timer is a good idea. If your gas-fired water heater has a pilot light it is not a good candidate for a timer, but the set temperature should be adjusted, if it is higher than 120 degrees.
Checking with your utility and/or the manufacturer to make sure your particular heater will work well with a timer is a good idea. If your gas-fired water heater has a pilot light it is not a good candidate for a timer, but the set temperature should be adjusted, if it is higher than 120 degrees.
Digital timer for gas water heater giving many choices for on-off cycles - $16.
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Simple analog timer for a gas water heater giving one schedule for every day - $6.
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