Inside the Staircase House (i)

Marc Dupuis, the builder of this infill on Primrose/Lorne staircase showed me around the inside. There are some “new” construction techniques and features that are worth looking at over the next few posts.

The house consists of a street level entry, kitchen, dining room, and garage. One floor up (the fourth) is the large living room and deck. One floor down (the second) are two bedrooms. The first floor, at the Primrose level, is a studio arrangement of bedroom, studio, bathroom, wet bar (aka kitchen) and separate entrance. All logic and good design suggests that the entrance at this lower level be directly from the adjacent stair landing but instead the city insists that the owners provide a separate, parallel stairs, via an easement over the adjacent property, down to the sidewalk level. I suspect this is so the city retains the right to “remove” the stairs some day in the future and just to complicate that would be reason enough to make the entrance off the stairs even if it wasn’t such obvious good planning for the site, the house, and the sidewalk/stairs. (the previous set of stairs had such an entrance off the landing until they were replaced about 8 years ago…).

These three white boxes mounted on the wall constitute the furnace and hot water supply for the house. The far box houses a tankless water heater. The water travels through a valve system …

(valves are not yet fully hooked up). The hot water from the gas heater is directed through the red pipes buried in the concrete floor. There are four zones on the first floor, so rooms can be kept different temperatures. The concrete is poured on 3″ of high density blue foam and a similar apron extends 3-4′ beyond the foundation.

Only the lowest floor level is concrete. Upper floors are conventional wood frame floors. They are also heated under the floor boards by plastic pipes attached to the subfloor. There are access hatches to valve systems set up on each floor to regulate and control the zones and water flow. Here is what the wood subfloor looks like from below:

The black paper stuff between the pipes and subfloor helps spread the heat so the floor does not feel like a bunch of hot and cold lines. There is no air handling ductwork in the house, saving on bulkheads and chases that are required to move air from one level to another.

In essence, the house has tankless, gas-fueled hot-water in-floor heating.

8 thoughts on “Inside the Staircase House (i)

  1. I’d love to see some more details about the total cost of a tankless hot water heating system. Sounds like a great fit for tight spaces.

  2. I just bought a tankless hot water heater that looks identical to that one.

    It was about $4k, which seems like a lot. We worked it out, and it’ll pay for itself before it wears out, and probably earlier if the price of gas goes up. It has the downside that you need to pay for it upfront, whereas for a tank you’d pay every month for a long time to Enbridge. Renting a water tank (rare anywhere else in the world) does not make financial sense unless you’re living month-to-month.

    It also has the intangible benefit of feeling a bit greener, but we wouldn’t have done it if it weren’t financially viable. Maybe that makes me a bad person.

    My only complaint is that it takes awhile to get hot water out of the tap in the mornings, but you can tune it. And the added space in the basement will be filled by most stuff we don’t need.

    I can dig up the exact price and model number later today if you’d like, chzplz. It is worth investigating.

    – A

  3. Thanks Alex: I agree, renting a HW tank is way too expensive. That’s why I own shares in Consumer Water Heater fund (ENF) (they pay me about 6% dividend).

    There is an article in this month’s fine homebuilding magazine on how to fix the long-time-for-hot problem, but they all involve routing a new pipe from near the furthest hot tap back to the HW heater.

    I have friends in Holland who have a similar tankless HW heater than runs water through wall radiators under the windows as the way to heat the whole house.

  4. how about operational costs for using it to heat a house? I assume it’s quite a bit more than your hot water consumption, but I wonder how it compares to a gas furnace.

  5. chzplz: I would think it the same or less than a forced-air gas furnace, for operational cost. This is because most people feel warmer when the floors are warm, so the actual air temperature can be a bit lower. Another way to look at this is to invert it: you can be in a room with normal air temperature and still feel cold because your floor is colder, often because it is over an underheated crawl space, cantelever, garage, etc or on a slab that is wicking heat out to the cold exterior. In those circumstances, no matter how high you raise the room temperature it feels cold. Warm floor = warm person.

    However, I have not been a fan of hot water radiator heated houses since they work best keeping the same temperature day and night, which means you may be overheating your house at night (a not-insignificant number of hours),or worse, opening a bedroom window for fresh cool air while similtaneously heating the room. While modern in-floor heating systems can be turned up or down, the response time (lag) is significant enough to discourage turning the heat down except for significant amounts of down time. There were a number of earlier posts on 37 eccles (use the search button) or go to their blog of the same name: they have a huge gas fireplace for quick response heat because the floor is so slow to warm up.

    I’d love to have more first hand response on the various systems.

  6. Now the details: ours is a Navian 180a and cost $3800 installed from Premier Comfort, maybe $2000 more than a tank. We ended up redoing some of the plumbing. It should pay for itself in 15 years or earlier.

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