One thing we encounter in these parts of the woods is that the trades will take days off to go deer hunting this time of year so we lose out on a few days here and there. I wish I could be out in the woods; maybe once this project is over I’ll have time to get back into hunting again.
I’ve spent the last two days giving tours to neighbors and friends as well as caulking all of the electrical penetrations in the drywall. Bob came out and did a preliminary blower test Saturday morning too.
Saturday was extra special because Christine and the boys brought me out McDonald’s for lunch. We had our first unofficial meal at the new house. Much fun. We made a makeshift dining table in the kitchen and ate our chicken sandwiches together. Followed up with play time in the warm sun on the front porch. Finally Christine and our oldest son helped pick up debris and throw it in the dumpster.
For caulking I used a low-cost latex white caulk from Lowes. I sealed around every electrical box, inside and outside walls. I also caulked all the ceiling lights. Caulking the inside wall outlets is probably not necessary but it is an added level of defense. Ultimately all the air in and out of the house will be controlled. We won’t let any air run around willy nilly in our house. No sir. For electrical wires and the flashing around the fireplace flue I used a red fire rated caulk. The drywall in the attic that was accessible from behind was caulked by our insulation contractor. Speaking of access panels, later on in the project I’ll put weather-stripping around the panels to assure air isn’t passing through them either. On a normal house they just lay a piece of drywall over the openings. This allows air to flow from conditioned to unconditioned spaces. In our house we’ll want to prevent that from happening so it will require special tactics.
As I said, Bob brought his blower testing equipment out to get a preliminary reading. We’re shooting for EnergyStar 2.5 rating on the house. It should perform beyond EnergyStar 3.0 but the only reason we’re not doing that yet is because 3.0 isn’t out yet. He set up the blower (essentially a large fan in a sealed door opening) on the front door and put tape over the obvious openings in the house: door knob locations, basement window side cracks, dryer vent hole, etc. The fan was then turned on and the equivalent of a 20 mph wind was hitting our house from the inside out. The fan sucks all the air out of the house through the front door. The air then needs to be replaced so it flows in from the outside through all the air penetrations in the house. As we walked around we could feel air coming in around the door frames, attic access panels, un-caulked outlet boxes and even a light box that was already “caulked” by the drywall crew. This then gave me an idea of what areas need additional attention. I also got to see first hand why it’s critical to caulk between framing memebers throughout the house. I could feel air coming though seemingly tight, nailed 2×4’s around the basement window. Crazy.
The preliminary blower test also allowed us to see where we’re at on our performance numbers. The numbers can be used to “right size” our HVAC system. The system will be sized for worst case scenario, but even so it may be smaller than what a builder would put in a similarly sized cookie cutter house. Full disclosure, I’m not an expert in what all the numbers mean, so consult your local home energy consultant. And I don’t know if our numbers are good bad or indifferent, but they look good to me. These numbers you see here are from the estimate; which was verified by the blower test that we’re on track. Our calculated peak load and required capacity for heating is coming in at 31.1 (kBtu/hr). For reference our EDGE60 pellet fireplace will output 52.5 (kBtu/hr). I’m not sure if this means the house could technically just be heated by the fireplace. The specification for our a typical house our size is 84.0 (kBtu/hr). On the cooling end of the ledger our required total peak load and capacity are 17.6 (kBtu/hr). With these numbers we should be able to get the HVAC system designed and set up to work well with our house while saving us money.
As far as whole house air infiltration goes the numbers are more difficult for me to understand but they are coming in as expected. If you’re into this sort of thing here’s where we’re at so far. Keep in mind once the house is complete the numbers should improve. ACH=air changes per hour (I’m pretty sure that’s what it means). For heating we’re at 0.23 natural ACH, cooling is 0.18. Don’t ask me why they’re different. Go ask your pop. ACH at 50 Pascals is 3.00 (still no idea what this means but Bob said it was as expected). CFM at 50 Pascals is estimated at 2050, and we came in around 2000.
For what it’s worth annual heating cost is projected to be $439 and cooling to be $116. Water heating should be around $183 and lights and appliances (which I’m assuming is way off) is at $1488, so we’ll re-look at that last number. We’ll firm up these numbers once all the mechanicals are in and obviously for sure once we move in. Stay tuned.
Pics from the last couple days: