HVAC for a remodel/Energy efficiency upgrade
2000 sq ft, basement and 2 storey, 80 years old home in NYC area,
The clients request is to have central AC priced out because they currently use window units which will spoil the advantages of the window upgrades we are planing; but it seems to me that there is economy in installing a new HVAC system because the gas boiler is at least 30 years old and suppling HW baseboard (House is warm )
The budget for this is to remain “near” $10,000.
Running ducts for forced air is to be kept to a minimum. We are not increasing insulation at this time so the the finishes are to be disturbed as little as possible.
So far the best I can come up with are what we call “closet units” for each floor ( Amer. Std. HVAC model AUH1B060a936 95% efficientcy rating + coil + condensor) Each unit will be fit into a closet or a new enclosure and a short duct will supply theother room(s) on the floor.
I also looked at High velocity forced air from but it seems invasive despite the small sized ducts and in the 15G to 20G range.
Also sizing is a problem since LEED level insulation will be added over the next 3 years.
Can anyone recommend an HVAC system/approach that provides the best effciency at this budget 10G to 15G level.
Replies
Are ductless mini split units an option?
The closet units are a good way to go given the limitations you have to deal with. (Heating-dominant climate; equipment to provide both heating and cooling; minimum ductwork.)
The sizing may well be a problem, and a room-by-room load calculation should be done that gives the loads for both the current level of inslulation, and for the future levels. My guess is that the calcs will show that each of the 3 floors, even with the current insulation, can be heated with a smaller (40k BTU) furnace, and can be cooled with a 2-ton condenser. The basement may not need any cooling if it is well below grade.
How about ... hydronic baseboard style? Might be worth considering. Piping can take up less space than ducts. Can also tailor the delivered temp to the weather a little easier. May be more easily modified as well when the load goes down with your future improvements. Hydronic could give you other options, too ... e.g. cabinet heaters. This doesn't do much for the A/C, though. But you might be able to combine the hot water source w/ a A/C system (instead of e.g. electric heat for individual room units).
There are LOTS of ways to handle the situation if you allow yourself to think outside of the normal 'residential box' ... but you have to be willing to dig a bit. Some of this might be considered a little routine in the commercial sector ... there are lots of products out there.
'Course, you pay your money, take your choice ... flexibility and comfort may ultimately come at a price. There may be no real easy solution ... otherwise you wouldn't be here asking others for options.
But whatever, if you cut a corner, you may get something less than desirable. This is the time to put in the effort for the best solution that fits all of your needs ... just be ready to make some compromises ... for there will ALWAYS be plenty of those to be made.
Is this DIY or are you going to dictate the system w/ the contractor? Is the contractor well versed in various systems or does he specialize in the routine/easy stuff? Maybe time to switch? Might consider a mech egr that has some good skills, but he may be hard to find.