I can now fully appreciate the benefit and even the necessity of a backup heating system in New England. In 2011 alone there were 3 or 4 storms that caused power outages, but I have been very lucky that they only caused minutes or a few hours of interruptions for me. Many others experienced days without power. On the other hand my solar heating system is in its first year of life and needs some serious debugging, so my back up systems are needed – often!
In this part of the world multiple days without heat in the winter can be life threatening. This, and the potential for frozen pipes, provide ample reason why insurance companies want to know the details of a home’s heating system, and it’s backup, before providing insurance.
My house (78 Main St) has a somewhat unique solar heating system with no oil, propane, or wood for back up. Electric baseboard is often installed as the backup for a home in New England, but we don’t like to use it because it is so expensive. And, electric backup is not a good alternative for the case of a power outage!
The main heating source for my home is a good sized solar collector with a large, seasonal storage tank. The tank is heated all summer and both the tank and collector provide heat in the winter.
For the last couple of months we’ve been debugging issues with the storage tank…which means I didn’t get much heat storage and I’m mostly heating off the solar energy of the sun each day. You may not be keeping track, but I have, and we haven’t had much sun these last few weeks – so my backup system has been kicking in and, I’m happy to report, working nicely.
Since I use hot water to heat my house (via a low temperature water to air conversion), I installed an on-demand electric hot water booster for the time when my tank is not quite hot enough to heat the house.
Back in late July I noticed that my tank was not heating up as quickly as it did the previous summer. After a few weeks the temperature in the middle of the tank hadn’t increased from 150F. The previous summer it had gotten over 175F.
After doing some measurements, I realized that the quantity of water in the tank had been increasing at a rate of about 10 gallons per day. My storage tank is composed of mostly sand with about 1000 gallons of water, which measured about 3.5 feet from the bottom of the tank (maximum height of 8 feet). In August I measured the height of the water to be about 5 feet and in Sept it was over 6 feet! Most likely this was 45F or 50F water coming in and cooling my storage.
So we have spent the last few months thinking and testing theories about how the water is getting into the tank. For a long time I liked the theory that the water was getting in from the town water connection (a leak) to the domestic hot water exchange tank which sits in the middle of the big storage tank. I went for many days and even weeks at a time with my domestic hot water turned off to test this theory. Fortunately, I belong to a heath club so I took a lot of showers there and heated water on the stove to clean dishes.
At this point we have ruled out a domestic hot water leak so we are working on understanding how ground water may be getting in. We’ve made some progress on that, dug some holes near the tank, and found some water pretty close to the surface, so now we are thinking about how to redirect that water. It is likely that ground water 4′ or 5′ below the surface wouldn’t be able to get into the tank and that the insulation is still intact enough to be a good storage. So redirecting ground water may work.
In the meantime, the backup systems for both domestic hot water and house heating have been well tested and I can report that they are working and I have both a warm house and hot water!