energy efficiency

So You Need a New Hot Water Heater

Condensing, tankless hot water heater (left) with drain water heat recovery unit.

The decision is usually thrust upon you. Shower water goes luke warm, or worse, stops altogether one morning. If you're lucky, the basement won't be all wet when you go downstairs to investigate. Yes, the hot water heater has died.

In the hectic days following, you need to make a decision quickly. If long-term energy security and environmental impact are priorities for you, here is a short guide to buying a new hot water heater.

Note: this post was co-written by a good friend of mine who is, in my mind, one of Edmonton's most knowledgeable experts on energy efficient retrofits. He recently installed the water heater shown above in his own home.

Solar Hot Water

The most efficient way to make hot water uses solar collectors, but if you don’t want to (or have the time to) go the solar route, your best option is to use our plentiful and cheap natural gas. Although electricity provides 100% efficient water heating, the electricity itself was generated at 30%-50% efficiency, often using dirty Alberta coal.

Tankless Hot Water Heaters

Using natural gas, the most efficient choice is a condensing, on-demand hot water heater (seen above). This means that there is no tank, and therefore no standby heat losses, and the combustion of the natural gas to heat the water is the most efficient. They have an energy factor (EF) of 0.92-0.96, and they cost around $3000-4000 installed. The combustion gases are near room temperature and are vented directly outside through the basement wall often using PVC pipe.

Predictably, I (Conrad) endorse the above choice. Long term, people! Think long term.

The next most efficient choice is a regular combustion, on-demand hot water heater (no tank, but the combustion is less efficient). They are vented up an existing furnace/hot water chimney or out the side wall using metal pipe. They have an energy factor of 0.82-0.84. (we have no info on costs - anyone?).

Hot Water Tanks

Next up are condensing hot water tanks. Their combustion efficiency is in the 96% range, but because of the standby losses of the tank the energy factor is around 0.83. They cost around $4000 installed.

Finally, there is the regular old hot water tank, which has been around for more than 100 years. Some are insulated better than others and energy factors range from 0.53 to 0.66. (again, no cost info, although this is certainly the cheapest option). 

Tankless = Durable

Besides energy efficiency, a compelling reason to choose a tankless heater is durability. Every tank will eventually corrode and spring a leak. The difference in life spans between tank and tankless heaters is significant. In fact, "Expected life of tankless water heaters is 20 years, compared to 10 to 15 years for tank-type water heaters" (source).

So there you have it. To me, tankless seems like the way to go, but obviously every situation is different. If you do decide on a tankless unit, Edmonton contractors are much more knowledgeable about them than they were just a few years back. Also, make sure to get at least two quotes, as I have heard of $1000 differences for installation and purchase of the exact same unit.

* The Energy Factor of a hot water heater is based on three factors: 1- the efficiency with which the combustion energy of the natural gas is transferred to the water; 2- the heat lost due to storage; 3- cycling losses due to startup and shutdown. 

More pictures:  read more... »

Personal Finance - Part 3, Investments

This is the final installment in a three-part series about personal finance for the conscious green Edmontonian. It covers:

  1. day to day finances
  2. retirement
  3. investments


The above picture is the world oil consumption curve. It is often displayed as just data, allowing what will happen on the down slope to our imaginations.

Peak oil is just one of many ways in which we are reaching the limits of our growth as a species. I find it highly absurd, then, that adults (you know, the ones who are all grow’ds up)  cannot rationally discuss the end of growth in polite company. And it’s virtually never discussed by anyone with any power. The fact of the matter is, infinite growth is impossible in a finite world. Let me repeat that:

Infinite growth is impossible in a finite world

Yes, it sucks. Yes, it’s inconvenient. But it’s true.

Maybe it’s a facet of denial, but it is easy to “understand” on one level about growth ending, and then turn around and invest our money in mutual funds and stock markets.

In my humble opinion, investing your money in stocks/mutual funds means one of two things:

  1. image The Unicorn Option - You believe that infinite growth is possible in our finite ecosystem. If this describes you, stop reading – the unicorns will deliver your fortune when the time is right.


  2. image The Playa Option - You recognize that growth will end, but you think that you’re smart and ruthless enough to get out of the stock market before all the suckers do (you know, your children and all those those other weaklings).

Option one speaks for itself, and I personally wouldn’t be counting on option two if my retirement was more than a couple of years away.  read more... »

Rona Home and Garden's Coal-Spewing Ways

Left: Home Depot’s modern, efficient lighting.  Right: Rona’s wasteful, antiquated lighting.

One of the hardest things about being aware and concerned about the environmental crisis is witnessing how many profitable planet-saving measures are ignored. Take lighting. Investments in new lighting technology can often pay themselves off in two years or less.

That’s why I’m frustrated with the approach taken by Rona Home and Garden. Rona’s President and CEO Robert Dutton recently claimed that “at RONA, we are committed to sustainable development from a social, economic and environmental perspective. This includes making a difference in Canadian communities…” (source).

And yet Rona store at 10450-42nd Avenue is wasting huge amounts of polluting electricity and money by lighting with 1960s-era technology. And that hurts my Canadian community.

Rona’s Dirty Old Technology

I did a walk-through recently, and came up with the following estimate of the 42nd Avenue store’s electricity use from lighting. This estimate is almost certainly biased in Rona’s favour because there is much information that I don’t know, so I’ve given Rona the benefit of the doubt as much as possible:

  • I estimate that there are about 500 metal halide lamps (lights) in the 42nd Ave. store (see above, right).
  • They consume, conservatively speaking, 320 Watts each (it could be as high as 460 Watts, but I can’t tell from visual observation alone).
  • These 500 lamps, assuming that they’ve been in service for 10,000 hours, consume about 160,000 Watts when turned on

On the other hand..

The efficient lighting used at, say, Home Depot’s 6725-104 Street store (pictured above at left),  could provide the same amount of light at a burn rate of 129,000 Watts.

Assuming that Rona has its lights on one hour before and one hour after closing, its lights are turned on for about 113 hours/week (source). If it updated to modern lighting, the Rona store on 42nd Avenue could save 3503 kWh per week, worth about $350. In case you’re counting, that’s 182,156 kWh and $18,216 per year.

Given that a kWh of electricity in Alberta is responsible for about 1 kg of carbon dioxide, Rona could therefore reduce the emissions of their store by 182 metric tonnes per year of CO2, while saving money in the process. It would be like taking 35 cars off the road for good.

Until Rona cleans up its act (in a profitable venture, I might add), its green claims will continue to ring hollow. Come on Rona Home and Garden! Do Edmonton and yourself a favour. Stop your polluting ways.

Note: My information comes from a contact that I have in the lighting industry. I believe that it is biased in Rona’s favour, and does not include factors such as motion sensors and variable lighting modes that could be incorporated with new technology.

Observations (Part 03)

front 08(3)

(photo courtesy of Edmonton Real Estate Weekly)

I have the first set of electricity consumption numbers for the house (see the data at the bottom of the post). Some comments about the numbers:

  • It was sunless winter. I found that sunshine had a greater effect on the performance of the house than temperature. People have commented that January was mild, but we burned a lot of wood because we only got 5-10 hours of total sunshine (92 hours is normal).
  • Our heating needs dropped off a cliff once the sun started shining on a consistent basis. In the last six weeks all of the thermostats have been turned off, and we have only burned two fires.
  • Of note: we installed water-efficient showerheads on January 12 (Bricor, 1.11 GPM versus about 2.25 GPM previously). Also, until January 12 there was another adult in the house (so  three adults, two children).

So far…

  • That said, we went through a LOT of wood this winter. We would burn for four hours straight in the evening and then another hour in the morning when it was –25 and there was no sun.
  • once the sun started shining, it warmed up, and we were using efficient shower heads, our electricity usage dropped to 8.6 kWh/day. We are very conscientious about power use, but on the other hand we cook a lot in the house.  These LAME numbers (lights, appliances and misc. electricity) are below our yearly estimate of 5150 kWh (8.6 kWh/day would be 3139 kWh annually).
  • our movable PV awnings are not yet up. The production numbers are for 12 modules out of an eventual 32 (the last 20 are bifacial).
  • the basement was not heated - it will be when someone moves in, plus they will be taking showers, etc.
  • Based on what I seen, I think that this house will be net zero house at least in the above average years. It remains to be seen if it will make the grade for an average year.

The numbers:

Total: 2009 Nov 9 - 2010 Mar 22 (133 days)
Total Household Use:   2451 kWh
Average Daily Household Use For Period: 18.4 kWh per day
Solar Energy Exported:   405 kWh
Solar Energy Used In-House:  223 kWh  read more... »