Thought I would add one more item. In the winter our house feels rather drafty when the sun is down and we are of getting any solar effect through the windows. We would like to have more consistent or even heat if possible and would consider electric radiant floor strips under carpet or wall heat under the two story windows if it would be an efficient and more comfortable alternative. Welcome to ideas. Thanks

I noticed that no one has responded yet, I think things are slow on this forum on weekends, so hang in there. I think the HVAC systems replacement will be straightforward and maybe your best bet is to get a few contractors in to give you some ideas and some bids.

The draftiness is a more complicated issue. Maybe you can get one of those audits with the infrared or whatever to see where the drafts are coming from. In our case, I got the most bang for the buck in both energy savings and comfort by replacing our windows and doors. Our electric utility even has a rebate if you use one of their contractors for the audit.

With the solar panels, I think the obvious type system to consider is a DF system, high eff HP with back up nat gas furnace. While you have correctly given your electric and nat gas rates, the wild card so to speak is the solar panels. This is really beyond my area of expertise and probably so with most of HVAC dealers. You might consider contacting a residential specialist at your electric utility for advice and/or direction. I have no idea what your budget is but I would think you would want to maximize the use of of the solar panels. This will involve a more sophisticated communicating system with good controls. I would start with Carrier/Bryant FAD dealers because of their GreenSpeed systems.

The draft effect is a separate issue which should be evaluated by a good dealer for suggestions to improve. Yes baling out here. Not really enough information to thoughtfully offer an opinion without on site inspection.

IMO

thanks for the responses. tiger, throw out the solar panels, just based on the gas and electric rates and home design, would think a HP would be better over traditional gas?

The reason I ask is that the solar panels system installed was to cover 80% of my current needs and i just consider it pre paid electric at a fixed rate per say. just based on rates listed above, would you still suggest an HP? i never have lived with an HP so curious if the lack of "hot" heat would be a comfort change.

I think you should take the conservative approach and assume they you will be buying all the electricity used for the heat pump. Heating with the either gas furnace or heat pump are close, It makes sense to spend an additional few hundred dollars and set up a dual fuel system. You will then have the option to use gas or electricity as the rates change.

Ok here is a fuel comparison between electric and nat gas.

I used 3 COP for HP and 96% eff for nat gas furnace. Keep in mind that this comparison is to be used for a guide only. There is slight leverage for the HP but without the solar panels I would advise against DF system.

Cost per 100,000 btu of useable heat

Electric baseboard: $2.69
Heat pump: $1.00
Natural gas: $1.10

It would be nice to know how many KWs can be produced on a sunny day.

IMO

Kenstl,

I just wanted to mention that if you get a few alternative bids from contractors, post the model numbers and I am sure that the folks on this board will help steer you in the right direction.

ok, so natural gas would win out in the above synopsis. in a normal gas furnaces, would running a fan all of the time help in moving air throughout the home and keeping a more even heat? I am experimenting running my fan while the heat is off the last couple of weeks and I am finding that the heat tends to kick on more as I assume air movement is better to the thermostat.

Regarding the solar, on the longer / brighter summer days i produce just over 50 kWh, over the past couple of weeks (november) with less sun, it varies from 5 kWh on very overcast / cloudy days up to 32 kWh. winter sun is lower and shorter hours vs summer. Until i have a full year under my belt, it will be hard to fully understand the true savings and production.

Thanks for the cost comparison. It may be better to stick with gas as the solar produces a lot less in the winter sun. the strength of our area is that is covers a lot of energy when our electric use is the highest with AC on.

That's a relatively small amt of electricity and really insignificant as far as heat pump heating. I would forget the HP and just go nat gas furnace with high eff AC. Certainly with this additional information, I would throw out my earlier advice to the trash can. You might want to consider a true modulating furnace probably 80 K size.

IMO

great, thanks for the input. i do not know much about a 'true modulating furnace' so i will have to read up on that. i assume those are an attempt to have continuous airflow? thanks, that gives me an initial direction to head.

tigerdunes, just to clarify the solar amounts. The summer / best days of sun will produce about 50-55 kWh per day. For a 24 hour period, that would equate to approximate 2,083 Watts in power. 50 kWh x 1000 / 24 (hours in day of production).

The totals should come to about 9,000 - 10,000 kWh a year. Thats averages to 24-27 kWh per day, but the actual amount per day will fluctuate from 0 to 55 kWh depending on the time of year, amount of sun per day, etc. We know the total yearly amount since my area avg 4-4.5 hours of sun a day as an average.

Winter on say a day of 10 kWh, that only comes out to 416 Watts for the day.

Thanks again for cost analysis, gas is the way the go. I would be going from an 80% to a higher efficiency gas furnace so I will see some savings on that end anyway.

thanks again everyone.

The fact that your solar panel system produces little KWs in the winter and only marginal leverage with HP heating versus nat gas heating tells me to forget a DF system. Put the money for an upgrade to a HP toward a high eff modulating furnace. Let the solar panels serve you best for electric usage in your home during summer months including AC cooling.

Modulating furnaces to look at would be Carrier/Bryant and Trane/AmStd.

IMO

Great thanks.