Heating systems for new home

[FlyingScot]

Originally Posted by sky's

mini splits ARE NOT super efficent in the winter. if you get the Mitsubishi with the hyper heat they are not "super efficent in the winter" and they should not be considered your primary heat source. we do alot of remodeling.

Have not heard "not super efficient" before. Our mini splits are virtually our only hear source in Mass, and they've done extremely well even on extremely cold days, like 5 or 10 below in the record cold of 2-3 years ago. Super cheap to run too--comparisons are tricky, but I think less than half the cost of oil.

We have Mitsubishi, I don't think our model has "hyper heat"

[DickR]

For a new house, your first thought should be to make it superinsulated and very tight. The cost to do this is relatively little extra, and the savings in heating/cooling costs pays for the extra cost in little time. The size of the heating/cooling system will be substantially smaller, with corresponding less cost. The house will be much more comfortable in all seasons, without cold spots.

When the air inside a home is so dry in winter that humidification is wanted, the reason is almost always far too much air leakage. Human occupancy produces moisture, and excessive air leakage flushes out that moisture, resulting in dryness. Excessive air leakage is something that costs money, makes the house more uncomfortable, and cannot be controlled. The old adage "the house should be tight, but not too tight - the house has to breathe" is woefully wrong. The occupants have to breathe, while the house has to avoid moisture accumulation problems. The only way to achieve the best result is to make the house as tight as possible and provide mechanical ventilation, so that the right amount of fresh air is provided all the time. In this climate (heating-dominated), efficiency is gained by heating the incoming fresh air with exhaust air, through a heat exchanger. The device is a heat recovery ventilator (HRV).

The thought of active humidification in winter for a house that isn't very tight should make you stop and think some more. Where is all that moisture going? If it is leaking out through the walls and into the attic space, you may wind up with condensation on cold surfaces where you don't want it, leading to rot and mold.

While geothermal heat is an option that functions well, with high coefficient of performance, the cost usually is substantially higher than for other types. However, if a new well is to be drilled for the house anyway, then the incremental cost of geothermal for a low-demand house can be more attractive.

Today's cold-climate air-source heat pumps have come a long way toward providing a good choice for heating and cooling. They can realistically provide all the heat needed down to below zero, particularly for a very well insulated house. To be sure, the energy needed to "pump" heat up from below zero air temperature to indoor temperature is greater than when the outside air is milder, so that the coefficient of performance drops accordingly. If you feel that you want supplemental heat for extreme conditions, then electric resistance heat is your best bet for the few hours each heating season when you may need it, being low cost to install.

The building science behind all of the above is well-established and easily found on sites such as greenbuildingadvisor.com and buildingscience.com.