tracey

two systems would be more than adequate.

you could put zoning controls for the main floor and basement system-I would recommend that. Keep in mind that basements that are partially or fully below grade have small heating and cooling loads.

you definitely want good insulation and adequate ductwork design for the bonus room. FROGs known as finished rooms over garage are notorious for cooling and heating.

Nat gas is available? If so, I would install dual fuel system for downstairs system and a high eff HP system with air handler and backup electric heat for upstairs system. NC has a relatively mild winter climate but summers can be a beast. you do want to take advantage of NC's reasonable electric rates. That's why I recommend the use of heat pumps.

I can make a couple of suggestions if you like.

Of course conventional HVAC for new construction do not qualify for the Fed Govt tax credit. Geothermal does qualify for 30% of cost with no maximum. Something to consider if you can fit it in your budget and have available land for the lines.

Here is a website on state rebates that might be of interest. I can not vouch for its accuracy.

IMO
Good Luck!

Here is a link that might be useful: Link to State Rebates for HVAC

Here I am in NC sitting in a 2 st house with daylight basement. Exactly what tigerdunes says - dual fuel on 1st floor, just hp on second. Basement isn't finished but will do zoned system off the 1st floor unit.

My only complaint at this point is not putting a humidifier on the 2nd floor. It is not the usual thing to do for my builder (but then again neither is anything else I did). It just seems a bit dry on a really cold night in the upstairs bedrooms.

At current NG rates, I don't think you save a ton of money doing it this way. But I expect that will change but you never know. Electricity might go up more than expected - but that is the good thing about dual fuel - you pick.

I am suprised tigerdunes didn't mention it - although I am sure his fingers get tired. Do variable speed - it is quite nice. I really love my 2 stage compressor also. It so hard not to oversize especially if you build a tight house and oversizing without 2 stages will make for a humid house.

I say it is hard not to oversize because you get paranoid about having a hot house in the summer and there is such a culture of oversizing. Manual J is great but I looked over mine recently and it had us with a "leaky crawlspace" - we have a basement and there is nothing leaky about it. I actually had them change out a unit after we moved in because someone made a mistake and put in a 4 ton unit instead of a 3 ton. The HVAC company head engineer recommended that I keep it (I didn't pay for it) because it would keep the backup strips from ever coming on in the winter. Well - I've never seen them come on anyway and it was cold this year. We rarely go to second stage on the HP anyway.

Assuming you have the control - do a radiant barrier and r-40 in the attic (although I recently heard that code went to r-38 from r-30). Foam all the windows and doors ($200 for my slightly bigger house). Do energy star certification if you get utility discounts for it (we do).

Thanks Tigerdunes and David. Good to know I won't need a 3rd unit. I'll do some research on "zones" and also dual-fuel and variable speed. Being in NC, I am more concerned with cooling (that's why we prefer basements over finished attics).

We had a whole-house humidifier in our first house and couldn't ever get it set just right for all areas. We have a first floor Mstbr, so I'm not too concerned with the 2nd floor (esp. after we get the basement finished for the game/theater setup which will temporarily be in the bonus room).

I'll have more questions, I'm sure......... David--wanna hire out as a consultant? :-)

I'm cheap.

You will be shocked and surprised to know that we have more than 2x the number of heating degree days as cooling degree days in most of NC. Everyone talks about the summer b/c they came from the north.

Wow, that does shock me that there's twice the "heating degree days" here. Interesting.

I just know that when I'm cold, I want to get warm and stay warm; and when I'm hot, I want to get cool and stay cool.

tracey

David is absolutely correct.

You want var speed blowers in furnace and air handlers. If you do decide on dual fuel for downstairs system with zoning controls for main floor/basement, I would recommend two stg furnace and two stg outside HP condenser.

Zoning with zoning controls is not for the faint of heart. GC and/or HVAC sub should have plenty of experience. Sizing of equipment and excellent ductwork design/sizing is a must. Qualify your contractor in these areas and better yet go visit a job they have installed.

IMO

Do the ENERGY STAR certification even if you don't get the utility discounts. Why because a certified verifier reviews and inspects the HVAC sizing and installation as well as insulation quality AND even performs quality testing.
You are in the EarthCraft House region - I would suggest talking with one of their Technical Advisors.

The reason bonus rooms are notorious for heating and cooling issues is poor building practices - ENERGY STAR and EarthCraft House addresses the issues.

Here is a link that might be useful: EarthCraft House Technical Advisors

My onlly gripe with Energy Star is the price tag. I trusted my builder and $900 would have gotten me some extra insulation. My builder had done ultra tight houses before and we had 50% of the energy star standard on infiltration. So we had half the standard - IMO not a very strict standard. There is a cat door and an attic stair door with just your basic weather stripping. The cat door has since been foamed and a second door added (poor cat) and a second level of sealing was done on the pull down attic stairs. Since those were probably the 2 biggest areas, we might be at 35% of the standard now...

David--can you tell me more about the cat door? We're thinking about making a "pass through" from the mudroom into a litter box area built in the garage (enclosed space). I'm tired of litter boxes in the house. It would go through the wall, not the door. Perhaps this is something like you've done--2 doors on each "side" of the same wall? How did the cat adapt? Ours will be kittens, so hopefully "trainable" (we'll acquire them after moving in.....we lost our 21-yr-old just prior to our relocation here).

Thanks.
Tracey

I am not exactly sure what you are being charged for the ENERGY STAR verification, but 10-25 cents a SF would be about average. Other programs like LEED are much more. So for the average 1500 sf home this should be $750 or less. How many people will put up the extra $$ for cosmetic upgrades and ignore upgrades to the basic 'skeleton.'

Just as an FYI - (we both have heat pumps) a friend's January electric bill was over $400 and mine was $185. Then add to that - my home is 1/3 larger, they just had their first baby, we have an attached apartment with my parents living there (so 2 full kitchens, washing machines,etc) and I have 5 kids - so 9 people live here and occupied 24hrs a day. In fact my utility bills are the same as they were in the 1400 SF 1968 vintage tract home (with newer HVAC) when I just had 3 kids and no parental suite....

Sound decisions at construction pay off year after year..... for most homeowners ENERGY STAR is a good foundation. Nationwide more than 20% of homes built in 2008 were ENERGY STAR in Alabama fewer than 3%.

So yes, there is an up front cost, but it is far less than the monthly cost of typical code based houses.

Thanks Andy!

Andy - just so we are clear. ES certification is a piece of paper. Even $750 is a lot of money for a piece of paper. Build to ES standards - even exceed them. But the piece of paper is only a piece of paper.

We have 2 doors on either side of the wall to the outside.

I've pushed the garage idea for the litter box but it didn't fly. Cat might get scared with a car coming in. Now an enclosed space in garage is not a bad idea. The cat door is hidden in a shoe cubby in the mudroom.

Yeah, I've kind of worried about a cat using the litter enclosure and the garage door opening with a car coming inside. I might need to rethink this, but I do know other people do it because a pet forum is where I got the idea.

David, not to be contrary, but the actual certificate/registration part of ENERGY STAR is $50. The rest of that is the time and effort of the person doing the plan reviews, on-site verification and testing. You can't do the ENERGY STAR quality work without those parts. And if you are going to go through that effort, why not spend the $50 and get the certificate that shows you did?

The issue with builders doing ENERGY STAR work without the third-party verification is some of the builders, get it and are doing that, others think they are and are not and others are just slapping in ENERGY STAR appliances and HVAC and calling it done.... So how does the average joe know whats's what? That certificate.

The same could be said of building permits. It is just a piece of paper. Why should I spend 2+% of the job on it? I know what I am doing....

The sad part is that many more builders think they are doing a great job then actually are. I say this as a builder of 20 years who has built some very good houses. But since I have understood the building science concepts behind ENERGY STAR. I am using my money more wisely, spending the same and getting better results.

It is very easy to exceed ENERGY STAR standards here in the Southeast, but not often done because buyers and appraisers like granite countertops and banks lend you money for them. Increased insulation? high quality HVAC? you'll have to squeeze that in the budget.

So what the certificate can do is give the bank and the appraiser a 'they did that' item, which they can attach value to - that makes it happen sometimes, but not always.

Find the right bank, and they are willing to lend for an Energy Efficient Mortgage (EEM) or an Energy Improvement Mortgage (EIM) those go through the same process as ENERGY STAR (in fact adopted the process for their program) but those products are geared to existing homes!

Sorry to be long-winded

Thanks for the extra information, Andy!