Sunday, November 21, 2010

The New Furnace Arrives

Ken and Domenic from Dave Davies Air Conditioning Heating and Refrigeration installed a beautiful Lennox Elite Series G-61-V Two Stage variable DC fan 90,000 BTU high effieciency Energy Star rated furnace on Wednesday. Here Ken is illustrating the Ontario Workplace Health and Safety Board approved method of conducting the initial tests of the new unit, which is said to reduce lower back injuries by a significant margin. Note these newer furnaces are much more compact and closer to the ground than the older models they are replacing!

I inquired about the very fancy Honeywell Prestige thermostat, just to see if it was worth considering. It was an additional $350 on top of the furnace which had a standard thermostat included. Since I was the only one who had ever even asked about one, and Dave's son had just pulled one out of his own house in favour of a newer model that chatted with his iPhone, they provided me his at no additional charge. Sweet! I will thoroughly test this state of the art thermostat over the next few weeks, then offer my opinions.

The thermostat comes with a remote control, which allows you to access basic functions from anywhere in the house.

A close up view of the new unit, with new inlet and exhaust piping, and minor plenum modifications to fit the smaller size unit. The Space-Guard air filter was kept, as it is in essentially pristine condition, apart from some cosmetic rusting on the back of the unit.

And for the final verdict:
Total estimate price (furnace, installation, condensate pump, new inlet and exhaust, plenum mods, and basic Honeywell thermostat): $3900 + HST = $4407.
Total actual price (furnace, installation, condensate pump, new inlet and exhaust, plenum mods, relocation of furnace switch, and Honeywell Prestige thermostat): $3900 + HST = $4407.

Three other local companies provided similar estimates at $3700 (plus thermostat), $4000, and $4450, all prices plus HST. And no, even though you see high efficiency gas furnaces advertised as low as the high teens and low two thousands, those prices are inclusive of all potential rebates, and are generally for made in china single stage ac fan furnaces, which barely meet 90% AFUE standards. If you want a manufactured in North America two stage furnace, with variable speed DC motor, EnergyStar rated, the going rate is around $4000 plus HST.

Additionally, the installation qualifies for an OPG rebate of $125, a manufacturers rebate of $150, and the province's eco-energy rebates of $650 will also apply (less the net cost of $325 for the testing) so the final price will be $3807

Monday, November 15, 2010

Cheap and Cheerful Heat Loss Calculation, And The Winner Is:

After reviewing the rather complex calculations for determining heat loss, which involve converting heat content of a cubic metre of natural gas to mJ/hour, then to kW, and back to BTU's, I decided if I can find the heat content in BTU of one cubic metre of natural gas, I can simplify the calculation considerably. From a variety of sources, natural gas has a heat content of 36,000 BTU / m3:

Take your total gas consumed for a four month period from November to February, multiply by your furnaces efficiency rating (GFUE%) and divide the volume by 2880 (120 days by 24 hours)

Multiply this by a factor of 2.4, which compensates for actual average HDD for the period to maximum HDD assuming a coldest day of -35 (I used 6360 design HDD for the period - 120 days at 53 HDD per day, versus 2680 actual average HDD from Environment Canada)

Finally, multiply this by 36,000, the approximate BTU energy contained in 1 m3 of natural gas, and the result is the appropriate sized furnace for your house (one that will work non-stop when the outside temp is -35 Celsius):

2490m3 * 0.92% / 2880 HDD * 2.4 HDD * 36000 BTU/m3 = 68,724 BTU

So it looks like the furnace of choice will be 90,000 BTU, oversized just enough to fill demand on the few days that may drop below the -35 design temperature, and if down the road we wish to heat the sunroom in the winter, among other things.

It seems the winner is Dave Davies from Stratford, who (seem to at least) have a fair and reasonable price strategy, a no nonsense approach to installations (they always install a condensate pump to a drain, rather than a hose on the floor). The furnace will be an Elite Series Lennox G61V High efficiency, two-stage with variable speed DC blower motor. Not particularly pretty, but hey, it's a furnace. And with a stroke of good luck, they will be installing a Honeywell Prestige HD 7-day fully programmable setback thermostat, with remote control.

Thursday, November 11, 2010

Late Update - Festival City Run

Having long completed the 7th Annual Festival City 10k Run in support of the Stratford General Hospital Foundation, I figured it was time to fess up and post my less than stellar results!

My parents arrived for the weekend, and since Katherine had decided not to run this year, I headed out with Roger (dad) and Alexander (my co-pilot) on a cold Sunday morning. I hadn't gotten as much training as I would have liked in, but enough to comfortably finish in the 50 something minute range without having to stop at all (at least I hoped!)

I finished in 53:34, having decided to do a slow start close to the back, which always costs about a minute at most. 26th place out of 40 in the 40 - 49 men's age group, and 164th out of 350 total finishers. Believe it or not, that was the slowest I have ever completed a 10k in, though I have only done a half dozen now. I raised $230 for the Foundation, so all in all, not a completely abysmal showing!

Alexander entertained the other runners by chatting them up a bit, and doing his part, with morale boosting stretches from his comfy and cozy position ahead of me in the stroller! Thanks to everyone who made a donation!

Wednesday, November 10, 2010

Geothermal? Unfortunately Not An Economical Idea!

There is lots of talk recently about going 'Geothermal', with many new homes, and older houses retrofit with so-called 'geothermal' or 'earth energy systems'. Basically they are a ground source heat pump, and use a closed coolant loop to extract the heat stored in the earth (usually 8 deg C around here) which is then delivered to heat the house, and returned to the buried loop to heat up again, and continue the cycle. These installations are costly, upwards of $20,000 to $30,000 or more, require large excavations or deep wells to run the coolant lines in, but do eliminate the reliance on fossil fuels.

I went to the Nextenergy site, which has a nifty little savings calculator, which tells me I currently spend $3350 on natural gas. If I convert to an earth energy system, my heating costs would be $2260, a one-third savings over my present heating costs.

NextEnergy Savings Calculator

Size: 2900 sf
Building Age: 41+ years
Number of storeys: 2
Insulation: Loose
Province:  Ontario
City:  Stratford
Current Heating System:  Natural gas high efficiency condensing
Energy rates incl. storate and delivery: 0.41$/m3

The problem is, last year I only spent $1730 on natural gas, and if you take away the $17 'monthly charge' and 5% for domestic hot water, that leaves about $1450 as the cost for natural gas for heating, roughly 40% of the amount that the calculator estimated.

It would be safe to assume the savings calculated by the NextEnergy site are a percentage, rather than an actual dollar cost. Going this route, I could resonably expect my home heating bill to drop by one-third, roughly $475 per year. Divide the savings into an 'after rebate' cost of installation of an earth energy system of roughly $17,500 (a pretty low estimate actually), leaves a break even period of 37 years! It will be the year 2047, and I will be 79 years old when the installation finally pays for itself.

Something tells me that a roughly 40 year break even is not a very good return on investment, as the entire system would probably have to be replaced, essentially meaning there would be absolutely no break even point. Further to that, a significant portion of electricity in Ontario is still derived from burning fossil fuels, so running an earth energy system is not guaranteed to reduce my 'carbon footprint'.

Tuesday, November 9, 2010

Furnace Sizing: Heat Loss Calculations

Since I am of the opinion that our broken down hunk of junk furnace is grossly oversized for the heating requirements of the house, I decided to do a heat loss calculation to do things properly. The existing furnace is a 130,000 BTU 92% efficiency, which I really think is in the order of half again too big, and that something like 90,000 BTU should have no issues keeping the house warm.

I found the CMHC website which has a fantastic article on replacing a furnace, including a detailed method of doing a heat loss calculation based on your fuel bills.

The only other information needed is data on heating degree days for the period you are planning to calculate, which are available at these two sites. The first link will have you search for a local weather station, and provides historical 30 year averages for the station selected. The second link provides a Canada wide average for each of the last ten years. Specific HDD values vary by location, and you should try to get both localized data, and compare this with the Canadian data, especially if you live in places that are warmer (Victoria BC) or colder (Fort McMurray AB) than the Canadian average.

Looking at our Union Gas bill covering November 2008 through February 2009 (actual consumption from Oct 21 2008 to Feb 17 2009), I then simply cut and paste the calculation portion of the text from the CMHC site, and went through adding my own numbers below:

Total gas consumption from December to March = 2620 m3

Estimating 5% of gas is used for hot water, gas consumption during the period for heating = 2620 * 0.95 = 2490 m3

Heating degree days for that period (from Environment Canada) = 2680 HDD

Heating consumption by degree day = 2490 m3/ 2680 HDD = 0.929 m3/HDD

Heating consumption (difference of -35 coldest, from 18 ambient) at 53 HDD/day = (53 HDD/day)(0.929 m3/HDD) = 49.2 m3/day

Where gas has an energy content of 37.5 MJ/m3, and the existing furnace has an efficiency of 92 per cent, then:

Heat loss at 53 HDD/day = (49.2 m3/day) (37.5 MJ/m3)(0.92) = 1697 MJ/day or (divide by 24) 70.7 MJ/h

According to the energy content of electricity, 3.6 MJ/h = 1 kW, then 70.7 MJ/h = 19.6 kW

This heat loss would require a furnace that produces an output of 19.6 kW or about 66,900 Btu/h (1 kW is approximately 3,412 Btu/h).

If we allow the CAN/CSA F280 permissible oversizing of 40 per cent, then the proper furnace sizing would be (1.4)(20,100 Btu/h) = approximately 93700 Btu/h.

The determination of the correct furnace size for a house is NOT an exact science. Ideally the furnace size that is most efficient for any house is the size that effectivly runs close to 'flat out' only on the absolute coldest day of the year. If it is too small, it will not be able to keep the house warm enough, and if too large, it has an easy time heating during extreme cold, and becomes less efficient in mild weather.