Sunday, 15 November 2015

Heating & Ventilation - Part 2

Now that the temperatures are starting to dip around these parts our minds are on staying warm indoors rather than cooling off in the lake. It's time to talk about how we will be heating Casa Tortuga.

Usually by this time of year, in any of our previous residences, I would have already been wearing a turtleneck for a few weeks and we'd have cranked the thermostat up to 24°C. The furnace would run almost constantly and there would be times, even though the thermostat said 24°C, there still seemed to be a chill that made me want to wear my turtleneck to bed. And I did sometimes...socks too. It was not fun...nor sexy for that matter. Anyway...

This is also the time of year when the clocks have been turned back and it's dark by about 4:30 pm that I wish I had a time machine that could fast forward through the dark cold months and transport us right into spring again.

This year sheds a whole new light on how I feel about the arrival of winter. With the sun getting lower in the sky every day we are benefiting from the solar heat gain. So now I look at the shorter days in a completely different way than I have in the past. I actually find myself looking forward to the next shorter day to see how much further into the house the beautiful sunshine will reach. To date, a sunny day will easily get the interior temperature to 24°+C, without the help of any other heat source.

The turtlenecks are still waiting for me. I say let them wait!

One thing Ras and I have both noticed is that 21°C feels warmer in this house than it ever did in the last house. 21°C was turtleneck temperature for sure (for me at least) in the last house and reason to bump the thermostat to 24°C. In this house, 21°C is perfectly comfortable. I continue to wonder if 21°C inside will still be comfortable when it's -21°C outside and the sun hasn't shone for 2 weeks.

It's the cloudy days for which we had to install the heat sources. So here's what heats the place.

Two Fujitsu air source heat pumps (16,000 BTU/h), one for each level.
One indoor heat pump head (white box on the wall, top right) on the main level.
One indoor heat pump head on the lower level.
Artwork still not hung making walls look too too naked.

Supplemental heat sources include...

Ditra-Heat in-floor heat in the master bath area.
There are 2 LED fireplaces in the house, one on each level. The electric
heat function was used toward our supplemental heat source calculations.
We only wanted the fireplaces for the (light) ambience. It's doubtful
we will ever use the heat function.

The building inspector was concerned we would have cold rooms in the house because the heat sources are centralized rather than ducted, therefore he insisted we wire for baseboard heaters in every room. Sacrilege! We wired to appease him but I refuse to let a baseboard heater anywhere near the place.

This past weekend we kept the door closed on the north-east-corner room on the lower level. There is no heat source in that room other than the east facing window. After 48 hours with the door closed the temperature was incredibly close to the rest of the house, almost imperceptible.

So far, the inspector has been proven quite wrong. I know it's still relatively mild compared to what we are in for but all the rooms in the house are comfortably warm. I haven't done my geek thing yet to measure temperatures room by room. That's a project I will get to. The ERV was just commissioned earlier this week so I didn't want to get too crazy measuring stuff until that was done.

Last, but not least. Our choice for water heating.

 80 gallon A.O. Smith air-source heat pump water heater.

We chose an air-source heat pump water heater for it's energy efficiency. Some would argue that the purchase price of the unit wipes out any savings gained by the lower energy usage. That may very well be true in this case too, but we needed the unit's efficiency and cooling capabilities to help with our passive house numbers. In for a penny in for a pound, as they say.

The water heater has worked like a charm...but it is noisy. The compressor runs at about the noise level of a canister-type vacuum. Until we get the insulated door on the utility room we have taken to switching the unit over to electric (silent) mode only when we have overnight visitors. I have checked the hydro website to compare electricity usage of both modes. The heat pump mode is definitely more efficient using about 4 kWh for one heating cycle vs about 10kWh during one heating cycle in electric mode.

Some advantages that this heat pump water heater has over a conventional water heater is that it cools the air in the room. That's how this water heater takes the heat from the surrounding air to heat the water. Our utility/storage room is plenty big enough to accommodate the air volume needs of the water heater so we have not noticed that the air temperature in the surrounding rooms is noticeably cooler. This cooling feature will come in handy in the summer. As well, it dehumidifies the air. keeps the air temperature of the utility room at the perfect temperature for storing wine. Bonus! Maybe the extra cost for the unit is not that bad after all.

That's enough for now...cheers,

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