Yes, a fan in the cathedral ceiling will push the hot air down to some extent. But a better and less intrusive system might be intake vents near the ceiling with a circulation fan that pipes the warm air down to outlet vents at the floor level. This system is independent of the forced-air heating system. This is pretty common in New England.

What you need to do is a function of what part of the world you live in.

We built green and used 5kw of solar panels on our roof, geothermal heating and cooling, closed cell insulation, passive solar design, all ductwork in conditioned space, wood stove and more. We are in CT, zone 5 and our total energy costs are about 1/3 of what they were in our old 50s ranch, even though our new house is larger and we keep it warmer than the old house. We pay more for cable than we spend on energy.

I strongly recommend you look into geothermal as it paid back immediately. There are quite a few posts about it on the renewable and hvac forums where you could learn more.

Insulation is also critical as, no matter how you generate a BTU, the longer you hang on to it, the better off you are.

Annie - just an aside, probably any new house should have a lower energy bill than the average cable bill...

Totally agree, where is the house? Any high ceiling will be more expensive to heat. If you insulate it very well, it will be less. If you heat with an economical heating system, it will be less. All those things cost money - reducing ceiling height does not.

So it really depends what you think of as expensive and how you are heating your house and where you live.

If you intend to live in the house for more than a few years, rather than assume the system will be based on a forced hot air furnace you should ask a professional HVAC designer to recommend a more efficient system based on the climate, house orientation, shading, fuel cost/availability, house design/insulation and your personal preferences/needs.

Electric heating in a bathroom floor should not be considered part of the heating system. Its purpose is to warm the floor for a short period of time.

We live the Seattle area in the PNW. And, even though we do not get extremely cold temps in the winter, it can stay in the 40's and 50's until May. It "normally" stays in the 30's during day and 20's at night during the winter Dec - Feb. In our last house we had whole house radiant heat and it was wonderful, however, this time we are on a tighter budget and do not want to put the $50k+ into the whole house radiant. But, I just want to be sure there is a way to keep the heat in the living space below 8' like the radiant did.

Annie - So even though the geothermal would be wonderful, it's initial cost would be prohibitive for us at this time.

Renovator8 - Yes, we are definitely going to talk to a HVAC person for the best system for the size and layout of our home. Also, I agree that the electric floor heating in the master bath is not a true heating system. I just want the bathroom to heat up quickly when I get up in the morning to get ready for work. We will probably have a separate zone for the master bath. (I think)

Are you sure geothermal would be cost prohibitive? The only difference in cost for us between geothermal and a regular heating and air conditioning system was the cost of the wells....but that was more than offset by the 30% tax credit we got, so it paid for us right away.

Of course your part of the world has completely different heating/cooling needs so perhaps it would be...your area may be mild enough to use an air-sourced heat pump rather than a ground sourced one.

Great discussion and points. Probably the MOST economical path to lower heating bills is ensuring you get great results on your Blower Door Test. Lots of good threads on this site about that. Going along with this is making your insulation continuous or eliminating thermal bridging as much as possible. The Building Envelope is the most permanent part of a home, the hardest to correct and improve once complete and has the biggest impact on our energy costs.

Agree with putting return grills up high and personally, dont see the need to do this separately. Fans carry an energy penalty so might as well tie this into the HVAC or ERV/HRV duct system.

Passive Solar Heating also makes a lot of sense if your site allows it. Sounds like your design might be past this point but this design method can be done with zero extra up-front costs and can reduce your heating costs by 40-90% depending on your design and building envelope.

Here is a link that might be useful: Cost Effective Passive Solar Design