After moving in, my first project was re-configuring and re-connecting our hydronic (baseboard hot water) heating system. During the renovation, much of the existing base board radiators had to be removed to replace floors. A new Dunkirk oil-fired furnace was installed in 1997. It is 85.2 percent efficient and has an output of 105 MBTU. That is not bad, but at the low end of the efficiency curve. These days you can buy a furnace that is 92 percent efficient. With the high cost energy, every little bit counts. In an effort to keep costs low, I kept the Dunkirk furnace and decided to increase heating system efficiencies by other means.

Zones:

Originally, the house was set up as a single zone. This is fairly common for this size house (approx. 1,600 square feet). By re-configuring the house into three zones, the temperatures in rooms that are not being used can be lowered. That alone can save 20 to 30 percent on fuel costs.

The three zones consist of the bedrooms and old bathroom (zone 1), the Master Bedroom and Bathroom (zone 2) and the Great Room (includes the kitchen, dining room, play area and living room)(zone 3).

Programmable Thermostats:

In each zone we installed programmable thermostats. These are set to cut back the temperature ten degrees over night and during the day when nobody is home. That will save about 10 to 20 percent on fuel costs. This is a Honeywell Model CT3500 Programmable Thermostat. It has four dayparts; Wake, Leave, Return, Sleep which can be set to any time of the day. It is programmable for Weekdays (Mon-Fri) and Saturday/Sunday. If you need to have a seven day program use the CT3595. We have ours set to Wake up at 6 AM, Leave at 8 AM Return at 5 PM and sleep at 10 PM.

Update: The CT3500 series thermostats have a convenient “Change Filter” reminder built into them. Every 90 days or so you get a slightly annoying “Filter” flashing on the screen. Of course hydronic heating systems don’t have air filters. Check this post for instructions on dealing with the filter reminder. This information is not in the manual.

Boiler reset controller:

This is where things can get a little technical. The Boiler reset control determines the temperature of the hot water running through the radiators. It has an outside temperature sensor that is mounted to the side of the house, and a water temperature sensor that is connected to the output side of the boiler. When it is really cold outside, it increases the average temperature up to the high limit which is determined by the boiler type. When it gets warmer outside, it lowers the water temperature and increases the amount of time the circulator pump runs. I have found that this works very well. We have had several nights in January were the temperature was below zero and the house stayed cozy warm inside. This should save about 15 to 30 percent on heating costs. The Boiler Reset Controller is a Honeywell Model AQ475A Aquatrol Outdoor Temperature Compensator for Boilers.

Update: For a complete description of the AQ475A click here for manual.

Insulating pipes

Current guidelines call for insulation of all hydronic heating pipes in “unconditioned spaces” An unconditioned space is anything that is not heated such as a basement, attic or garage. I purchased the thickest black foam pipe insulation I could find. It has an insulation value of R5. I don’t know how much money this has saved, but I am sure it is contributing to the over all system efficiency.

Auxiliary Heat Sources:

We installed a Jotul Nordic F100 wood stove in the living room(I will blog about wood stoves later). When the wood stove is burning, the Great Room zone does not call for heat which saves additional money on oil. We chose a UL listed airtight stove. These stoves are much more efficient that older models and when installed and operated properly they are very safe. We don’t use it all the time, but it is nice to have a fire on those cold January nights.

Altogether, I would say those changes have had some effect. Last winter we used about 500 gallons of heating oil, which is considerably less than our neighbors.

Getting the work done:

Unless you are a plumber or an HVAC technician, most of this work will need to be done by professionals. Using a torch in an enclosed space near combustible materials can lead to a fire. Improperly installed boiler controllers and temperature limit controllers can lead to serious malfunctions of your heating system and may damage or destroy the boiler. This is very serious equipment. Most zone valves require that they be installed with the water flowing in proper direction. Improperly installed zone valves will lead to loud bangs and clunks when the valves close against the flowing water.

Things a typical homeowner can do is change and program the thermostats. There are several models to choose from at your local Lowes or Home Depot hardware stores.

You can also work with your HVAC contractor to get your heating system set up the way you want it.

If you have some basic plumbing skills such as soldering (also known as sweating) and you feel confident that you can do the work safely, then it can be a challenging but fun project with some quick returns. Look for some good plumbing blogs in the future.

The less oil you burn this year, the less of your hard earned money will go to Big Oil. It is also is good for the environment. Burning one gallon of #2 oil (home heating) releases about 22 pounds of CO2 into the atmosphere.

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