Energy efficiency measures

At the outset of the project, a key objective of ours was to increase the energy efficiency of the new house. We looked at fancy stuff like geothermal heat pumps and photovoltaic solar, but all those technologies are evolving rapidly, and now doesn't seem like the best time to invest. So, we planned for what I'd call conventional "best practice" energy efficiency. Here's a summary of those measures, and how they've worked out so far:

• No central air conditioning

There are usually about 10-20 days in Boston with temperatures near or above 90. So far, on those days we can keep the indoor temperature down just by closing windows during the heat of the day, then opening the house and using the whole house fan in the evening.


• No fireplace or internal chimney

This was a big aesthetic compromise, but I think it really helps keep the house tight.


• Exterior 6" walls, insulated to R20


• Efficient double-pane low-E windows

We have a lot of large windows, and clearly lose a lot of heat through them in the winter. We did try to minimize glass on the North side, however.


• Attic roof insulated with icynene foam and double radiant barrier

The semi-finished attic has a small crawlspace on top, which is vented in the summer with a Broan attic fan (1200 CFM), acting as a simple and quiet whole-house fan.


• Hydronic (hot water) baseboard heating, one zone per floor



• High-efficiency, modulated-flame, condensing gas boiler

A Weil-Mclain Ultra 80 boiler, properly sized, theoretically runs at about 92% efficiency. "Modulated" means that it reduces its flame when it's not too cold outside, analagous to shutting off cylinders in
a car engine that doesn't need full power. It doesn't run at full capacity until it's -10 degrees F outside.


• Indirect water heater

A Weil-Mclain Ultra 60 gallon tank is heated by a dedicated "zone" of the main boiler. Water temp is turned down to about 120 deg F, since the dishwasher and clothes washer (both Bosch)
have their own internal heating for sanitization.


• Compact fluorescent and LED lighting where appropriate



• Non-metallic ducting for all exhaust fan penetrations

Sometimes the ducts for bathroom fans or dryer vents are made of aluminum and create an efficient "thermal bridge" from the inside to out. We used plastic components. For the kitchen exhaust fan, by Nutone, we found a rubberized canvas sleeve by Excelon to connect to the outer vent.


• Bathroom fans are still a problem...

I think we lose a fair amount of heat through the bathroom fans in the winter. There are energy-recovery systems for these that we should look at sometime.

Gas heating costs, winter 2008

Here's a tabulation of our gas bills for last winter, which totaled about $830 for heating, excluding the average $32/month we use for hot water.

• Domestic Hot Water usage is estimated based on our summer bills
• Total cost excludes National Grid's $13 connection fee

Roof insulation performance, warm weather

The cathedral ceiling in the third-floor/attic, an unvented roof insulated with icynene foam and a double radiant barrier, seems to perform well in warm weather. We didn't install central air conditioning (too expensive both upfront and operating cost), and we both have office space in the third floor, so we depend on that roof insulation system for comfort both winter and summer. So far, in hot weather the attic temperature is always lower than the outside temperature, which I think is pretty good.

Boston's had our first heat wave the past few days, and I took some measurements today. We keep most windows closed during the day, opening them at night to pull cooler air through with a small "whole-house" attic fan.

Location	11 am	3 pm
Outside air	89 F	93 F	air temp
Exterior siding (south wall)	95	114	surface temp
Exterior shingles (roof)	132	152	surface temp
Attic ceiling	86	92	surface temp
Attic air	83	89	air temp
Second floor air	81	84	air temp
First floor air	80	82	air temp

The cathedral ceiling is only 6" thick (made of 2x6 rafters), so all that separates the interior drywall from the 150-degree shingles is 6" of icynene foam and the 1" radiant-barrier airspace.

Happy New Year

It's our first new year in our new home. The house is wonderful, both in our everyday life with the complications of work and school days, and for the entertaining we've started to do. It has performed well in the winter and there are no real problems in any of the structures or systems.

I haven't posted here for a very long time, but have a backlog of material I'd like to get online, including interior painting progress (about 2/3 done now) and heating system performance (good).

House completed

Here's the house just before the move last Wednesday, taken with the new Lumix camera B gave me for my birthday. The house is complete and ready for occupancy, the landscape is about half done.

Michael Shea is our landscaper, his guys Kevin and Roger are building the stone walls using Pennsylvania Flats. The wall along the driveway replaces the one from the previous house. The walled garden beds below the front porch also serve a functional purpose: they reduce the drop off the porch to 18", so we don't need a safety railing across the front.

The front walk will be made of the S&H bricks from the back porch of the old house.

Painting prep

We're painting the interior ourselves. This means we're also prepping the interior ourselves. Originally this wouldn't have been too bad, since the house came prepped and primed from the factory. But then we ripped out about 400 square feet of various walls and ceilings for building inspections and rework.

The plasterers who finished the attic also did the patching. They tried to use plaster as much as possible, but where they were joining with the factory drywall they had to use joint compound (mud).

I didn't fully appreciate the difference then, but I sure do now. Plaster veneer is skimmed on, flat and level, and is extremely hard and virtually unsandable. It has to be done right the first time. Drywall mud is soft and sloppy, and cannot be done right the first time. Instead, you put too much on and then sand it off flat. This took me a week of late nights, generating more than 10 pounds of fine dust.

But now all the plaster/drywall is prepped pretty well, with a coat of a sealer called GARDZ that seals in the alkaline lime plaster for painting.

Almost there

Sorry for the long delay. I lost my camera, and have been terribly busy.

The house is completely working, and has passed its final electrical and plumbing inspections. Final fire and building inspections will be on Tuesday, and we move in on Wednesday, May 30.
My birthday is Tuesday - someone has a BIG wrapping job ahead of them.

We may not actually have a certificate of occupancy on Wed. It can take up to 10 days for the city health dept to sign off on occupancy, although there's no inspection involved. But there's no problem moving our possessions, and the worst case is we have to spend nights at our neighbors house.

More plastering today

The plasterers didn't finish on Friday, plan to finish today.

Systems up and running

The electricity is on and complete, all lights and outlets are working. The gas meter was installed on Friday, and we turned the boiler on on Saturday. So now there's water and hot water.

We're preparing for final electrical, plumbing, and fire inspections later this week.

Sheetrock tomorrow

Attic walls and ceiling go up tomorrow, along with patches in the rest of the house, like the kitchen and entry ceilings which we opened for plumbing work. Everything is insulated and wired and ready to be closed up. My son and a friend of his helped me pull several runs of hot pink cat5e ethernet cable from the attic to the basement last weekend, along with a shielded cable for balanced audio between family room and attic.

I also ran simple phone wire to connect our telephone ringer, a nice two-tone bell that Betsy's grandmother rented from AT&T for some 40 years. After her grandmother passed away, Betsy called AT&T and told them the bell had been paid for decades ago so we were keeping it.

Electrical service?

Our electrician Chris Veliotis, setting up the electrical service again yesterday. This is our third or fourth attempt at this problem, and I think we've finally got it.

Electrical Code requires that the main service line stay clear of any window opening, such as that bathroom window on the corner, by 36" to each side and by 0" on the top. The code also requires a "drip loop" before the wire enters that conduit. Although the code allows the electric company to be pretty sloppy about how they install that drip loop (they can have 12-18" of extra slack), the final result can't violate the clearance requirements.

If you then add our inspector's incorrect calculation of the roof clearance requirement, and my desire not to run big ugly conduit all across the front of the house, you get quite a puzzle. The miscalculation was calling our porch roof flat, even though its pitch of 2.5:6.5 is greater than the required 4:12 - which means the service line has to be 8' above that roof, instead of the 3' requirement for a pitched roof.

But third time's a charm, and with that little turn around the corner I think we'll be fine. We might even have electricity this week.

Laundry room floor

The laundry room is on the second floor, near our bedroom. The washer and dryer are Bosch Next 500 models, which are high-speed front-loaders. The word is that they can vibrate a lot, although you can minimize that with proper levelling. So we wanted a floor that would dampen vibration and absorb noise.



The structure of the laundry room turns out to be ideal, and I still wonder whether MSI did this deliberately. The floor of this 5x6 room is supported by 6 engineered joists, which are connected only to the band joist at the edge of the house. That is, there's no direct connection between the second floor structure and the first floor ceiling, they're decoupled. We added some 2x6 cross-bracing for good measure.

The actual floor is 3/4" plywood with 1/2" durock. The tile is set on a waterproof membrane, so we don't need a pan under the washer to catch water: in the unlikely case of failure, the little water the washer holds can just leak onto the floor. (Washer pan/drains are problematic because they aren't allowed to drain into the sewer.)

Under the floor is 4" of rock wool for noise control, plus rigid insulation around the exterior. The laundry machines will rest on 1/2" compliant grommets.

I hope this makes the laundry room acceptably quiet, because I don't know what more we could do.

Kitchen tile

Our tile sub, Bob Ziegler, will finish the first floor kitchen/hall tile today. In this (lousy) picture from Saturday he's about half done, the diagonal layout means lots of pieces need to be sawcut.

The upstairs tile is all laid square and will go quickly, he'll be done this week.

It looks beautiful, I'm very glad we opted for diagonal layout. Will post cleaner pictures later.

Fire retardant paint and fire safety

I ordered an intumescent paint additive which adds fire retardance to any latex paint, mixed it into a can of white primer, and gave it a quick test. It works!

The stormboard on the left was painted with plain latex primer. The stormboard on the right was painted with the same primer, with an additive called Flame Stop III mixed in. They were both exposed to a candle flame. The untreated board is shown after 90 seconds, when it ignited and sustained flame. The treated board is shown after 180 seconds, and still hasn't ignited.

Intumescent coatings work by forming a foam at high temperature. In a thick industrial coating, the foam would be inches thick and really fireproof the structure. In a thin paint the defense is minimal but significant.

We'll use this primer in the kitchen, behind all the appliances and cabinets.

Other fire-safety measures include backing the refrigerator, dishwasher, and stove cavities with rock wool, and wrapping bathroom fans with UL94-V0 nitrile foam. These materials are all good sound absorbers, as well as fire retardant.

Then there's all the building-code measures, like sealing floor penetrations with fire retardant caulk and foam, hardwired smoke detectors, egress codes, etc.

Attic radiant barrier installed

The outer half of the radiant barrier was installed today in the attic - all that shiny aluminized housewrap. The early returns suggest that it works: air temperature got up to 83 degrees today, shingle temperature reached 135 degrees, but the attic temperature didn't get above 85. The attic is still completely open to the rest of the house, until the walls are built, so it's absorbing all the heat load from the house as well as solar.

The rest of the barrier goes right under the drywall. I'm going to leave the lower half (cripple walls) unfaced, to avoid more interference with wireless signals. So far both cellular and wlan signals seem to be unaffected.