I need some input on an HVAC balancing question --- I have a raised ranch home with a finished basement and an open stairwell connecting the two floors. It's an early '90's build originally equipped with a heat pump. All registers for the basement are along the ceiling and it was equipped with an electric space heating wall unit in the finished front half of the basement and electric baseboard units in the laundry room and half bath down there. The heat has never balanced properly (probably the reason for the electric space heaters in the basement which we don't use because of the cost). The difference between the upper floor and the basement is 10-20 degrees or so lower in the winter. Since purchase we have installed a sealed combustion gas furnace along side and tied it into the ductwork for the heat pump (which has saved a lot of money). In the past 5 years I have audited the home and sealed bypasses in the kitchen soffit, plumbing chases, cantilevered front facade, sealed most of the wiring penetrations in the attic, dealt with 5 panned returns (one of them which was connected to the back of the bathtub space) and insulated the small space under the front entry. All this got the BD from 2,500 CFM@50 down to around 1800 CFM@50 (which made it less drafty on the top floor but not warmer in the basement). Closing registers either partially or all together still doesn't seem to help much either and creates moisture on the upstairs windows(double pane) now that the house is tighter. I'm at a loss as to what to try next.
Kari, unless you have mechanical ventilation your home is tight enough. 7 ACH@50 equates to about the .35 ACH natural rate. If you do have it then make it as tight as possible.
All bathrooms and the kitchen have fans ducted to the outside. Since I got it down to 1800 I have some moisture on the upstairs windows during heating season I'm working on getting rid of too.
Kari, You didn't note that you did a duct leakage test. If not, I would suggest that first (total and leakage to outside), then airflow at each supply & return to be sure the air is getting to/from where it should. If you don't find a good fix then I would look for a good HVAC designer to look at correct airflows to each room/area. I have found many homes with very poor air return, just based upon my general knowledge/experience/senses. Something I regularly see is supplies-only in basements, no returns. I hope this is of some help to you.
I haven't done a duct leakage test. I don't have a duct blaster or training for that although I've looked at videos about it. The ductwork is f/g board trunks and flexible. The ductwork seems to be installed well although it isn't done with mastic. There is no ductwork outside the envelope. I know lack of return seems to be an issue in a lot of homes but this home has 7 returns! Each bedroom (3 upstairs and 1 in the front corner den of the basement -- also the main upstairs hall and the basement family room and one in the kitchen which we recently blocked off) * As I said in a reply farther up the page, they were all panned into walls and such so we addressed that by stuffing bags of f/g in wall cavities above the return, etc. In my area/state I haven't come across anybody who is doing duct testing. Not even WAP agencies. I know an instructor/trainer who I might be able to twist his arm to come do it when he has time if that is the most helpful next step -- actually skip that, I don't think he has a duct blaster either.
I have been doing test and balance for 20 yr. most test and balance people use very high end tools, $40K or so hoods, hot wire, air presser gages, RPM meters, Amp meters, temp, RH gages. step one find the air flow for that air handler/ motor system its listed on line if its ARI.org use the right coil. email me and will send you a list of what is to be done www.ericsenergy.com Then I do heat loss heat gain room to room. turn this to CFM per room then use your best ways to test air flow to each grill. Lets say you need 1000 CFM total but the air handler can only do 900 CFM then you put 9/10 in each room or grill. Keep in mind its just plus or minus 10%