Saturday, September 27, 2014

How to Save Money and Energy Despite Having Electric Baseboard Heat

When I purchased my most recent home, one of my big concerns was the heating system - specifically, electric baseboard heat. I've been living with gas heat for years - hot water baseboard, forced air in Hartford. I was concerned about comfort, of course, but mostly I'd heard much about the high cost of electric heat.

Now there are many innovative adaptive heat controls out there (the Nest device is particularly interesting, and worth it's own blog post at some point) - but for the most part these low voltage controllers are not designed to work with line level voltage used by electric baseboard heat.

Savings Opportunity #1: Zoned Heat

Balancing the cost of electricity, electric heat brings one big benefit - it's inherently zoned. Which means, instead of one thermostat for the whole residence, or perhaps two (upstairs / downstairs), most electric baseboard heaters have independent heat controls, called thermostats. My space (a small condo) for instance, has seven thermostats: living room, kitchen, master bedroom, spare bedroom, two bathrooms, and the basement. So there is a lot of possibility for fine tuning the heat - to heat just the spaces I commonly use, and perhaps save some money.

Savings opportunities include turning down the heat, and closing off unused or little used spaces, and  turning heat down in the bedrooms during the day, and other living spaces at night.

Savings Opportunity #2: Install Digital Thermostats

When I moved in, all of the thermostats in the place were old-school electro-mechanical devices. There was no visible temperature reading or feedback, the rotary dial was exceptionally coarse (with a resolution of 10ºF) , the calibration was highly suspect, and the heat control was simply ON / OFF. If the temperature dropped below a set point, the device turned on 100%, the space heated, and the device eventually turned off.

Such a system is prone to "heat creep" - with the resident feeling a little cold and turning up the heat without a lot of thought to what the actual temperature is (and then acclimating to the higher temperature), and without a good reference to turn heat up or down consistently.

So the first step in saving money is to install a Digital Thermostat. Such devices are available at home improvement stores for about $25 each. Make sure you purchase thermostats intended for line voltage (120/240 VAC) as opposed to low voltage devices intended for oil / gas furnaces.

An aphorism I picked up in the corporate quality world was "If you measure something, it gets better" and the digital thermostats have a thermometer on them providing immediate feedback to the resident. So instead of simply "feeling cold", the resident can look and see the actual temperature. It's amazing how much things like health / energy / activity, as well as the ambient humidity and outdoor light level, affects a person's perception of temperature. So with a digital thermostat, the resident can now see that the room temp is 65ºF (or whatever the comfort level is) and put on a sweater or sweatshirt rather than nudge it up a bit.

In addition, the digital thermostats have a much finer resolution (1ºF) which means even if the resident decides to warm it up a bit, s/he can restrict that to a few degrees. Finally, the digital thermostats use proportionate triac controls - which means that the heat is not simply ON / OFF, but might have four settings: ON / LOW / MEDIUM / HIGH. As the temperature drops, the heat turns on LOW - and if that's enough to warm the space, it never gets past that. So the heat control is more subtle / even and therefore more comfortable.

The electrical installation is fairly simple - comparable to changing a light switch. The only complexity is that the older thermostats are DPST (Double Pole, Single Throw) - which is to say they break both lines (in many cases, the baseboard uses 240 VAC with two hot lines). The digital device is SPST (Single Pole, Single Throw) - so one of the baseboard lines needs to be connected directly.

Savings Opportunity #3: Install Programmable Thermostats

Now, simply adding digital thermostats still leaves a lot of room for energy waste - if the resident neglects or forgets to turn the thermostats down at night or during unoccupied periods. In addition, turning the thermostats down at night means waking to a cold home. the next step is to add programmable thermostats to key areas: the living room, the master bedroom, the basement. This device is a bit more expensive: $50 at home improvement stores.

It has the same general functions as the digital thermostat, but adds a programmable function. The device shown in the photo permits four different timed settings per day (typically WAKE / LEAVE / RETURN / SLEEP) and can be programmed differently for weekdays (Mon-Fri) and weekends (Sat-Sun).

An example of heat programming: 
  • Drop the house down to 58ºF at night; some folks like a cool house to sleep
  • Prior to normal wake-up time, heat the house up to 65ºF or a comfortable temperature. 
  • During the day, drop things down to 62ºF (if at work or out of the house). 
  • Increase heat to 65ºF in the late afternoon for the remainder of the evening. 
One of the benefits of a programmable thermostat is that if the resident wants it a little warmer, or happen to be hanging in the living spaces during the day, they can bump the thermostat up confident that it will reset at the next timed change, and not leave the house warm indefinitely.

One downside of programmable thermostats is the need to program the thermostats and maintain the clocks (daylight savings time). The Wikipedia article cited above in fact notes: 
Difficulty with usability in residential environments appears to lead to lack of persistence of energy savings in homes...In addition to potential increased energy consumption, digital programmable thermostats have been criticised for their poor usability. 
But if one is committed to energy (and cost) savings and thoughtful about programming these devices, they can provide real savings. Hopefully, in the future, "smart devices" (such as the Nest device designed for low voltage systems)  that communicate and self adapt to resident patterns and habits will eliminate the need to manually program devices in the future.

Additional Savings: Cleaning Electric Baseboards, Positioning Furniture

In addition to thermostat upgrades, cleaning baseboards periodically will help to improve airflow - even a thin layer of dust will impede the convection flow such devices rely on. In addition, keeping space in front of such devices will prevent hot spots and permit even heating - consider using bricks or pieces of wood to space furniture away from heating units and permit greater air flow.

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