Typical panel services are 200 amps. You want to install 2 something's that pull more than half of your available service. That's not doable with a standard service, much less solar. And why 2? A well placed propane unit of the appropriate size is more than adequate for whole home usage.

Wow, thanks for all the good input. I didn't intend it to become a debate about solar, but found that interesting as well. I'm not familiar with the lease program that is mentioned. I'm looking to have an array installed that will be owned completely by me. I can get a 20kw system installed for about $60,000. There is a new Duke Energy program offering $1 rebate for each kw installed, so subtract $20,000. Then there are 55% state and federal tax credits, reducing the investment further to $18,000. The system should generate about $2,500 in energy per year (assuming 9 cents per kwh), resulting in about a 7 year payback. There is also potentially a benefit I can derive from depreciating the asset, but am not sure that is allowed, so need to check with my tax expert. I think the main different between now and before is the $1 Duke rebate. Without that, I agree the payback period would be too long (about 11 years), but a 7 year payback seems reasonable to me. There is always the possibility of repair costs in the first 7 years which could lengthen the period a bit, but the warranties on the panels at least are much longer than that. In any case, I think it is a worth a try. With regard to the water heater question, I agree that two heat pump units might be too many, as the one in the basement might be idle for long times, so am not considering doing 1 heat pump (for the upstairs which will get used daily, but shouldn't use more than 80 gallons per hour as there is only 1 shower), and then a gas powered tankless for the basement. We have natural gas that will be already piped to the house for the stove/grille. Any other thoughts or suggestions are welcome, thanks for the lively debate!

Full disclosure - I own a Tankless gas water heater and love it. I had a 50gal tanked gas water heater before. Due to space constraints, it could not be replaced. It was in the doorway of the utility room. Here is what I learned when looking at Tankless water heaters. Just like when you want to go solar, you have to get more efficient with your appliances. The things I did to change my plumbing fixtures were intrinsic. All these things below were done as part of replacing aging fixtures and were not related to the tankless decision but made the decision and experience with tankless flawless. Replaced all but one bathroom shower valve with a Thermostatic valve. The last one will be replaced this winter. Replace all shower heads with units that used no more than 2.5gal/min Replaced all bathroom and kitchen faucets with units that used less than 2.5gal/min My dishwashers and washers already heated their own water and all but one of my Washers can use all cold water as input. The dishwasher and washers were energy efficient and used small amounts of water. There is a large bathtub in the house and the tankless water heater is wonderful for this. We take a bath maybe twice a week. I am getting a separate temperature controller for the tub bathroom so that the filling can happen without interfering with other activities. Currently, showers take priority. My house hold has 3 adults in it and we always seem to be in the shower at the same time (3 full bathrooms). With the tankless water heater, this is no longer an issue. I like in Maryland where we get really cold in the winter:-). I have a recirculator with my tankless water heater and that is on a timer. It runs for a few hours in the morning and a few hours in the evening. When the recirculator is not running, it takes about 1minute to get hot water to the farthest location in the house. I may add the point of use tankless heater to the bathroom faucets just because it wastes time to wait for hot water. This issue with hot water at the farthest location was always a problem. I purchased the largest residential tankless water heater which with a 30degree rise, will get you 9.6gpms. This would theoretically allow me to run 3 showers and a faucet at the same time. My unit is programmed to 110F degrees and the showers are set to about 105F degrees. The thermostat for the tankless is in an easy to reach location in the hallway and I can easily increase or decrease the water temperature. I originally started at 140F which is the max temp. I changed it the first day when I could barely wash my hands without burning them. My temperature rise in the summer is about 35F degrees and 50F degrees in the winter. When I went with tankless, I had heard all the horror stories of cold water sandwiches, huge volume drops due to cold incoming water and flow rate to get started at the sink. I have not experienced any of this. I think the thermostatic valves in the shower contribute to this quite a bit. I am able to get hot water at the sink in under 10 seconds except for the farthest unit. When the recirculator is running, the water is hot within 2 seconds. Just enough time to flush the water from the steel part of the faucet. Propane would be my choice in your situation. Electric tanked or tankless water heaters would leave you in a lurch when the power went out. Propane tankless water heaters don't perform as efficiently as the natural gas units but that is true of all propane appliances. I have my tankless water heater hooked up to an uninterruptable power supply in the event of a power failure which we have quite often. I also have a small gasoline back up generator and the tankless unit works fine when connected. I have a Rinnai RUR98i. This unit has a built in recirculator pump. You can also purchase a separate recirculator with the tankless or tanked unit of your choice. I purchased it from build.com and my plumber installed it. I also installed the scale water filter before the unit and this keeps the unit operational without a lot of build up. The unit is just over a year old and I performed a maintenance in the summer. There was very little build up. I am also installing a whole house filter for sediment and chlorine due to some work the water company is doing in my neighborhood for the next year. I have not selected a solution yet for the whole house filter. Good luck with your decision.

I like tankless heaters, I installed them in the last two houses. But there are things to understand about them: 1. Tankless heaters are very expensive to install when done as a retrofit. 2. They take an extraordinary amount of gas at one time - so you have to have the gas supply. Having the supply to run two of them would be unlikely. 3. They do take longer to supply hot water. 4. they do need regular maintenance So again, let me suggest a hybrid electric heater. These don't require venting at all. They cost less to use than even a tankless heater. They will cost much less than a tankless to install and there are often large rebates from the power company. In addition they will dehumidify your basement. They will give you hot water faster. There is an 80 gal available rather than installing two.