In hot water

By Selena Randall

We have had an interesting couple of weeks. First our water heater burst late on a Friday afternoon, and then the gas went off following the pipeline explosion. Our experience of living without gas is a topic on its own, but I would like to take you through the decision making process we went through to replace the hot water tank.

Our gas hot water tank was probably as old as the basement – 25 years old, so the tank was at the end of its life, inefficient, and poorly insulated.

As transitioners, when something needs replacing, we always ask ourselves the following questions: do we need it? What is the most energy efficient option that will help us reduce our personal enegyy consumption?

Having lived for 10 days boiling water for dishes and washing, and made full use of the showers at the sports centre I can safely say that YES we do need a water heating system providing hot water on tap! But with up to 25% of our energy bill going on heating water it’s a significant appliance in any house.

According the Natural Resources Canada most residential heaters have efficiencies between 55-60%. Energy Star rated tanks have to have at least 67% efficiency. Higher efficiency (and more expensive) tanks have 70-80% efficiency.

With a house that faces south, we have been thinking about going solar for hot water at some point, so we have borne that in mind in making our decisions.

If we went for a new, but more efficient tank, it would be larger than the old one but with thicker walls, and inconveniently wouldn’t fit in the hole left by the old one. We could run this with a solar system but we would need two tanks – one heated by the sun that feeds into the gas water heater tank which tops up the temperature as needed.

Our experience in Europe was running a condensing tankless system (98% efficiency) – the water is heated on demand when a tap is turned on by a central gas heater. This worked well and we were pleased to see that such a system is available in Canada. We tested the temperature of our incoming water last week (likely the coldest it would ever be), and calculated that the flow rate would be more than adequate for our needs. If we go solar later, we would have one tank heated by solar power, which would effectively preheat the water going through the burner all year round. The rise in temperature will give us a greater flow rate and allow more taps to be on at the same time, but use much less gas.

We decided to go tankless – pricewise there was little difference compared with a highly efficient tank, with most of the costs being for installation.

Our water heater is fitted now, and today we have used about 130 litres of hot water – about half a tank’s worth, for less than half the gas, and more than half the money – a simple way to reduce our gas bill by 15%!