Oil was out, since the earth is supposed to be running out of it — about a week on Tuesday if doom-mongers are to be believed. Not environmentally correct, in any case.
Gas would have been cheap and had eco credentials, but wasn’t available on the site. Lately, with our own supplies almost gone, Ireland has been importing most of its supply. And with the Russians starting to turn off the gas to Europe at the drop of a hat, the chances of it staying a cheap fuel are becoming slim.
But shenanigans on the Ukrainian border aside, at the Bonsall house the nearest main, in our neighbours’ garden, wasn’t suitable for tapping into, according to Bord Gais.
Something to do with pressures and pipe sizes. But equally deterring was 11 grand — the sum it wanted to charge to put a new line into the lane.
Propane was an option, but finding a space for two huge and unsightly storage tanks was a big issue. And isn’t propane made from oil? Or is it cow farts? Nope, that’s methane. Nowhere to graze cows, so that’s out too.
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It had to be something more eco-friendly, such as hamsters rubbing sticks together or having the kids alternating on a treadmill in the garden.
The architects and our tech guru, Peter, had suggested wood pellets. These are strange-looking nuggets of mashed-up wood, pulp and squirrels (okay, not squirrels).
You load them into a large hopper and the stuff is burnt to order by the control system. Combustion is achieved by squeezing the nuggets into an airtight chamber and setting fire to them with a giant hairdryer, otherwise known as a combustion starter.
Once they start burning, the hair- dryer stops blowing and the pellets smoulder away to heat up water, which in turn heats the house.
A pellets company has just started up in Northern Ireland, using home- grown timber. So we ordered a wood pellet system from Austria.
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However, when we measured the site, we found we’d overestimated the size of the space we’d have to fit it into. No room for a giant hairdryer.
Our builder, Ger, was once again giving me his “what now?” look.
Then a plan F came to me: “A heat pump!” I exclaimed.
“A heat what?” “A heat pump. They work by a gas compressing a motor that produces heat . . . No, the motor compresses air which expands the gas, no . . . Never mind, they’re small, efficient and very economical to run.”
A call to our tech guru confirmed that heat pumps were sufficiently environmentally friendly to warrant being used. “So how do they work?” I asked. “It produces heat by compressing and expanding a gas which extracts the latent heat from the air and . . .”
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He lost me there. But if Peter had said there were pixies with matches inside a box, I would have believed him. He just has that way about him.
We had seen a system at a show where all that was needed was a unit inside the house and an evaporator and pump unit mounted outside. After searching the pile of brochures, we were on the phone to the local supplier in Wicklow, Ola, a Swede who has lived here for 20 years.
Ola asked me to tell our plumbers that the pipes needed to be pulled out and redone entirely. I can still picture Anto the plumber’s face as I explained that a set of pipes he had installed had to be relocated on the other side of the utility room. “What, all of them?” “Yes, you see we need a pipe for the expansion of the gas in the compressor of the evaporator return . . .”
“Stop, we’ll do it. At extra cost of course!” Of course.
Anto finished the reworking, the Swede waded in and the system was commissioned without a hitch. And it really does work like magic. Although be warned, it does resemble the back-end workings of a local Spar shop.
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We have the system heating up during the night using cheap-rate electricity and storing large amounts of hot water for use the next day. And as the building is so well insulated, it takes just a little heat to keep it warm.
The cost of the system, excluding radiators, was €6,000 installed — higher than a conventional gas boiler and the equivalent of four years’ oil heating costs. But over the life of the building, the savings in running costs will more than pay dividends.
Now it was installed, I was determined to understand once and for all how it worked. I asked Peter to explain.
“Think of a fridge, warm at the back and cold inside, right? This is because heat in the air inside is extracted from the fridge and released outside. Your heat pump does that in reverse, taking heat from the ground or air outside and releasing it inside your house.”
To be more precise, it uses a refrigerant, a substance that boils at a very low temperature. Imagine the refrigerant is in gas form. With a certain amount of heat in it, it takes up a space the size of a football. Then take an electrically powered compressor and squeeze the football down to the size of a ping-pong ball. The heat becomes concentrated. This concentrated heat is used to heat the water that heats the house. Simple really. And not a pixie in sight.