Quote:
Originally Posted by JC3
For what it's worth, I have been looking into various heating systems for a new construction. More than one builder has told me geo may not be the best suited in this region. All seemed to say the same thing, too cold up here and more suited for climates more south than New England. I don't know how true that is but I will have an analysis done and see how all sources will work.
I was also told, depending on the house and the layout, one source may not be as efficient as another for that particular home. I was told this can be done by laying it out on a computer which will take into consideration sliding doors, windows, area..etc.
Does this make sense or am I being told something that might be misleading?
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You are being told the truth. The modern way to build and equip a home is to take detailed plans and subject those plans to various "computer models" that will determine the anticipated heat loss from the completed envelope.
The devil is in the details of course. The kind of windows and their efficiency rating, the kind and installation method of insulation, and even the perm rating of the paint to be applied to the interior walls is important.
The type of heating system that is to be installed is important, but not the only defining factor for heating efficiency. The "conventional" way to heat a home in Maine in "modern" homes built after 1900 is fuel oil. The traditional way to heat a Maine home is by using some kind of wood burning appliance. Both of those methods pump an awful lot of energy right up the chimney. And if the house is exceptionally tight, there are air quality problems associated with that that must be countered by an air exchanger. Air exchangers, as well as hot water/air heating boilers run on electricity, so despite the tightness of the home and the efficiency of the heating system, there may needs to be an analysys that will compute the amount of electricity that the house will consume in order to provide a true picture of the cost of operation of the house when completed.
I heat my modern, conventionally insulated home using three kerosene burning, externally vented wall furnaces (a total of 48000 btu of energy from three units: one Monitor and two Toyostoves). I burn around 500 gallons of kerosene annually. Sounds pretty good in a three bedrooom, two bath home, designed to be heated this way.
Oh, but wait: these three units will consume electricity and drive up my electric bill by around $30 at least per month when they are all working. So whatever the consumption of kerosene is per month, times the cost per gallon, plus at least $30 per month during the heating season is the true cost of heating this house.
I am in the process of planning our new home which we hope to begin building in the summer. We plan to use a hybrid energy system which will utilize the prevailing average wind speed by wind turbine plus a photovoltaic array and battery system that will enable us to be completely off grid. Our first choice of heating systems is a geothermal heat pump which will heat the insulated slab on which the house will be built. The manufacturer has told me that the heat pump will consume around 2500 watts to run: that's a LOT of electricity and may mean that unless the wind speed is high enough, we may have to use something else for heat.
We have also looked into evacuated tube solar thermal systems, and these are very interesting, especially since there is a relatively limited need to electricity to operate them: once the heating cycle has begun, the actual pumping of fluid into and out of the tubes is by thermosyphon and the electric pumps shut down.
There are quite a few of both of these systems in operation in Maine now, and quite a few that work exceptionally well. But the manufacturers of both systems have been very careful to tell me that the systems will be sized to an average of around 80% of annual need, and in the worst of weather...such as the twenty below zero mornings that we are enjoying right now...it will be necessary to have some additional heat source as the heat pumps will not by themselves generate sufficient heat for worst case scenarios.
One of the ways that we are thinking that we can add heat is by using propane since we will have propane on site for cooking, clothes drying, and probably for the generator. We could augment the "alternative" heat source using a small propane burning appliance such as a Rinnai wall furnace, or even a propane water heater in line with the radiant heating system into the floor. A wood stove might not be the solution for us since my wife has some issues with wood smoke effecting her breathing, although that would be the cheapest additional heat source IF we have spent the money for a chimney and hearth (which I am not sure I want to do).
But regardless of which system we will choose the first step will be to design the most efficient envelope, have a detailed heat loss analysys performed, and then make sure that the overall housing envelope is as efficiently built as possible.
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