Attic Hatch

I was asked recently about how big does an attic hatch need to be.
The answer is clearly stated (as clear as it gets) in the Ontario Building Code (above).

For a single family home the typical size is defined by the ceilng framing at 24" on center leaving a MINIMUM finished opening of 21 1/2 wide by a 24" long.

If you ever think you' d like to go in there then make it 30" long.

LowE Glass

I got talking to a client about LowE glass today. This was for a retail building in Toronto with some pretty large glazed areas. I was trying to explain the importance of LowE glass especially on the North facing windows.

To clarify the explanation I prepared the following estimation of heat loss. I'm sure there are tools out there that would do this but I thought I'd get a better understanding from doing it from first principles.

Sealed Unit Energy Comparison

Sealed Unit Assembly

	SHGC	VLT	U - W/(m2 ·C)	U – Btu/(h·F·ft2)
Clear/Clear	0.70	78%	2.8	0.47
LowE/Clear	0.43	53%	1.8	0.32
Clear/LowE	0.66	73%	1.8	0.33
Clear/LowE + Argon	0.66	73%	1.6	0.29

SHGC = Solar Heat Gain Coefficient

VLT = Visible Light Transmittance

U = Heat Loss Factor (Winter value used here.)

Energy usage calculation:

Area = 10’x17’ + 3x 5’x8’ = 290 ft² = 27 m²

Heating degree days (Toronto) = 3650 C·day

(temperature difference from 18 deg C inside)

Heat Loss = Area x ΔT x U

= 27 m2 x 3650 C·day x U W/(m² ·C) x 24 h/d x 1 k/1000

= 2365 kW·h x U

Now you won’t actually heat for every degree day. Many days will be warm enough that the natural heating inside (people, machines, sun etc.) will overcome the heat loss. So lets assume that 25% of the heat loss is covered by these gains and 75% by electrical heating. My last bill worked out to 11 c/kWh on average but the actual incremental rate is higher due to graduated pricing. Lets use the 11 c/kWh

	U - W/(m2 ·C)	Heating kWh/year	Cost $/year	Savings/Year
Clear/Clear	2.8	6622	$730
LowE/Clear	1.8	4257	$470	$260
Clear/LowE	1.8	4257	$470	$260
Clear/LowE + Argon	1.6	3784	$420	$310

Sealed unit performance data from the Pilkington website.

Fireplace Options

I have had a client who is interested in a Planika Alcohol Fireplace.
I'm pretty sure I don't like them but I have a well known aversion to open fires in my house (especially candles).
They seem pretty interested to I put together the following comparison to a DIRECT VENT gas fireplace.

Planika PROS:

• - easy install
• - does not require chimney (though ventilation of the room is required). Manual indicates that for a room of less than 350 ft2 you will need to have a vent fan operating or open a window.
• - burns fuel from renewable source (ethanol is of dubious environmental pedigree). Don’t fool yourself into thinking you are burning plants.

Planika CONS:

• - fuel is 8 $/litre
• - Needs to be re-fueled manually with flammable, liquid fuel (think fondue pot). Spilled fuel will remove latex paint and most hardwood floor finishes. I did a quick scan for a MSDS (Material Safety Data Sheet) for Fanola and it comes up as de-natured alcohol an excellent industrial product but all around dangerous. Eg, store in non heated room, explosion proof electrical, wear personal protective gear, hose down spills and retain water runoff etc.
• - Heat output is limited. Manuals state 1 L of ethanol per 2 to 5 hours means output is 1300 to 3200 Watts (4400 to 11000 Btu/h)
• - Needs to be lit manually
• - All the fuel needs to be burned. Don’t leave fuel in the burner as it may create flammable gasses and smell.
• - Cannot refuel the burner when it has run out. Must wait 10 minutes.
• - Seems to fall into a grey area of regulation. Probably classed like a candle and therefore has no specific build code, gas code etc restrictions. I would consider it a GREY market product.

On the other hand the Direct Vent Gas units I favour have the following:

D-V Gas PROS:

• - direct vent unit is separated from the indoor air. Combustion air is drawn from outside through a special vent and exhaust is directed outside
• - many units have “milivolt” controls and can be operated without electric power. They provide back-up heating in case of a blackout situation. The unit I had emailed a link to produces about 18,000 Btu/h (5300 W). Other, single sided units are more efficient.
• - remote control or wall switch actuation or thermostatic control. If you want a fire you turn it on when you are done you turn it off.
• - Units are “light” weight and can be installed at any level. Cabinets could be located below the unit I think but I’d have to confirm with manufacturers’ government approved details
• - Fuel is cheap and already available in your house.

D-V Gas CONS:

• - burns natural gas and creates green house gas (CO₂ from fossil source). Albeit at pretty good efficiencies. Direct vent units are on the order of 60-75% thermally efficient when operated without a fan. Higher with a fan. Compared to the best forced air furnace (like yours) at 95% AFUE. I would be pretty confident in saying that there is less green house gas emission per BTU of energy into your house from a gas fireplace than from Fanola fuel.
• - Can be hot. If the unit is too large for the space. Many units have thermostatic controls or Modulating controls so a smaller fire can be created.
• - Regulated as a gas burning appliance. Not sure this is con but must be installed by a licensed installer and there are rules about clearances to combustibles etc. will require a CO detector on the same floor.

The really environmental choice is a wood or wood-pellet burning fireplace/stove.

Lifebreath Clean Air Furnace

We are currently doing a second story addition project on a house with a two year old mid efficiency boiler. Don't start me on that.
For the second floor heating we decided to go with forced air indirectly heated from the existing boiler. This will allow for the installation of a high SEER A/C unit for cooling of the entire house.
Rather that a generic air handler I specified a CLEAN AIR FURNACE by Lifebreath http://www.lifebreath.com/en/consumer/products/residential/caf/
This unit combines an air handler, circulator pump and HRV in one cabinet. We will also install a Bathroom Vent Kit (more about that in a later post).
The increased cost of the unit is somewhat offset by the elimination of individual bathroom fans.
The unit arrived today with the HVAC subcontractor and we set it in place. We will be installing it in a hall closet on the second floor. I'll keep you posted as to how it all goes.

First Post - Where to start?

I'm a professional renovator working in the Toronto Area and I am constantly researching and testing materials and techniques for my ongoing projects. I would like to create an environment for sharing this knowledge with others and create a discussion about how things are being done in residential construction in this area. What materials are being used, what new products are people trying and what do we really need. Please post your constructive comments and we'll all learn something new.