I have a ~2,900 sq ft house built in 2000 in the Washington DC metro area with a Carrier Infinity compressor (model: 24ANB724A300) and 2 indoor evaporators (model: CNPVP2414AL). The house layout is a bit unusual (see floor plan). In 2019 I had a blower door test done that indicated an ACH of 16, so Ihad the swiss cheese batt insulation on the floor of the multi-section attic removed and replaced with 2″ of closed cell spray foam and 14″ of blown cellulose. Our gas heating bill went down about $1,000/year so the ROI on that particular ~$6,000 investment seems pretty good.

Unfortunately, we still have some indoor air quality and comfort issues in the house. Specifically:

1. The 2 upstairs rooms (Kids’ BR#1&2) tend to be uncomfortably hot compared to the rest of the house (even compared to the landing area outside the utility closet which itself is often unbelievably hot despite having a louvre door), and the air in the bedrooms is often stale/stuffy.
2. CO2 levels in multiple rooms in the house are usually between 1,000-1,500 ppm. My understanding is that well-ventilated buildings are half that.
3.热成像表明空气leakageat the 1^stfloor powder room (see blue line in floor plan), which is no surprise because the floor of that bathroom and the under-stair storage space are both freezing in the winter. Is a few holes in the interior wall and spraying the cavity with a froth pak the cheapest/safest way to address this? I am an ABAA level 3 installer, so I know the proper way to detail a wall from the outside, but I suspect that opening everything up to do it right will cost way more than can be reasonably justified by utilities savings or comfort.

我想要一些帮助优先投资olutions, whether that’s retrofitting an ERV, mini-splits, re-doing ductwork, etc. I am willing to pay for such help, but unfortunately most of the knowledgeable professionals I’ve found in this area seem to focus exclusively on commercial, multi-family, or new construction. I spoke to an executive at one company who mainly does volume new construction and he said that they could help me, but that it would likely be $1,000 for the inspection and another ~$4,000 to design the hvac/ventilation system based on the inspection, plus hiring a 3^rdparty HVAC contractor to implement the new system. I’m willing to spend some money, but $5,000 just to figure out what to do seems excessive.

Does anybody have any suggestions? Alternatively, is there a professional in the DC market you would recommend I hire?