BradH70 said:
I'm not sure that an "On Demand" setup would burn less oil though. My wife is home most of the day with my 2 1/2 year old son, so I'm sure that the hot water is being used more then if the house was empty all day. And with that, an average of about 0.8 gallons is used each day to keep the water hot. The Boiler Mate is one of the most efficient units on the market for an off boiler system. I'm looking for an alternative that will guaranty a cost savings over oil.
I just have a furnace in my house for heat and hot water. We rent. We moved in on July 1 and are only staying for a year. Early in July, I got sick of listening to the furnace kick on all the time to heat water, so I asked my wife if it was okay if we just leave it off and turn it on when we need hot water. She's a sport, so she was game. I have two kids, 4 years and 2 years old. When they need a bath, we flip on the switch to heat the water and when it is up to temp, we turn it off. With that hot water (in just the furnace) the kids get a bath and the wife and I get a shower (or two). It takes 3-4 minutes to get the furnace up to temperature and because the switch is off it doesn't turn on again. My furnace is rated at about 140k BTU and it's about 80% efficient. I'm not sure if that means that it burns 140k BTU of oil per hour or if it burns 175k BTU of oil to get 140k BTU of heat. Either way, I figure that we burn less than 1/10th of a gallon of oil every time we turn it on (which is either every or every other day in the summer). We lost a bunch of oil by leaving the furnace running for the first two weeks of July, but made up for that the rest of the summer. By the end of Sept, we had burned less than 30 gallons of oil for hot water. It was refreshing to see all of the neighbors get oil deliveries and know that still had 7/8 of a 275 gallon tank. Landlord even contacted us as she was concerned that the tank was perilously low and in danger of flaming out the furnace. That's a different story, but I assured her that we were fine. When doing dishes, we actually heat the water for washing dishes in the microwave. A small tub of soapy water cuts through the grease and then we rinse with cold water. That way we avoid running the water for 2 minutes just to get hot water to the tap. Overkill? Sure, but it's saving us money and more importantly keeping the money out of Big Oil's filthy pockets.
Now that I'm heating with my furnace (because the fireplace was determined to be no good in the beginning of Dec) I flip the switch on at 6am to heat the portion of the house that we use.. It's a total of about 1800 sqft and we have 3 zones. We run the heat in the loop that covers the dining room, kitchen and living room in an early 70's poorly insulated raised ranch in southern RI. We leave the bedrooms and the finished basement off. The ancient thermostat is set at 64 which makes it 68 in the heated part of the house. In the evening, depending on outside temperature, we'll shut off the furnace sometime between 3 hours and 30 minutes before its time for the kids to go to bed which means that the furnace is off for around 12 hours. We use an electric heater to keep one bedroom at about 70 degrees and let the rest of the house go. It got down to 14 degrees a couple of days ago and the house (minus the bedroom) was 43 degrees. I thought about turning on a fan to get some kind of wind chill factor going. I ran around the house with a IR Laser Temp Gun to make sure that I wasn't endangering any of the pipes by doing this and the coldest place I could find by the front door was 2.5 degrees C. In the morning at 6am, I flipped on the switch for the furnace which labored to bring the temp back up to 68 by 8am where it sat for the rest of the day. I checked the change in my electrical usage in Dec vs Nov and we have gone up 10kW per day,(a 50% increase to 30kW per day) so at .13 per kWh we pay an extra $1.30 per day in electric charges to keep our 1320 W electric heater going.
Do I need to save the money? Not really. Its become kind of a game with the landlord. We're supposed to use this one oil company and she's convinced we have been buying oil from someone else. She just doesn't get it and has even threatened to evict us. With all of that labor, we have been on this tank of oil for 6 months and it still reads 3/4... The house is a comfortable 68 degrees when we are home during the day and we have hot water when we need it..
So to get to your initial question, I think it's two questions. 1. How can I save money now with my current system? You can do what we are doing. You're in a slightly colder climate, but I'm sure your home's insulation is much better than mine. 2. What will save me money in the future for my DHW? That's the burning question. I heard someone talking about doubling or tripling electric rates with all the coal fired power plants they are shutting down this year due to EPA issues. Will crude go to $200/bbl or will the economy slow down and send it back down to $50? Can you get access to a supply of wood? If so, maybe you can heat your house with an add on wood boiler and use the pellet stove for aesthetics and use the wood boiler for your DHW. Maybe you can defray some of your costs for electric with solar panels or for oil with a solar hot water system. Other than that, the only thing I can think of is to capture some of the heat from your home to warm the water in your cold water supply line to your boiler add on prior to entering the system. Perhaps a few loops of copper tubing will warm the water a few degrees.
I'm by no means a professional in this industry.. far from it. I've just had one too many trips to the middle east and as such do everything I can to minimize my use of oil, even if I do have to use it for now. And I still have the full support of my wife, or at least I haven't seen the divorce papers yet.. haha.
Merry Christmas to you and yours.
