Energy monitoring has helped us make a surprising but sustainable business decision. We’re no longer rushing to change the shower in Beech lodge over to the solar hot water system as there is no energy saving case for it. Let me explain.
Since last summer I’ve been following the energy consumption of our lodges and cottage pretty closely. I take meter reading after most bookings, and work out the energy use per night and also per guest night for each holiday.
Two of the lodges have all their hot water on solar systems with immersion top up (they sleep 4-6 people). Larger Beech Lodge sleeps 6-8 and has solar hot water for its bath and basins (with immersion top up), but not for its shower, which is on-demand electic. Otter cottage is different – and I’ll come back to that!
After we finished the solar installation, we meant to change the shower in Beech Lodge over to solar hot water in the autumn, but held off, worrying that the winter sun in Devon wouldn’t be anything like enough to provide hot water for a potential 8 showers a day, and that the immersion heater would be slow to keep up too – especially as we have a timer switch limiting the immersion heaters to two hours on at a time.
And now, the energy monitoring confirms that this was a good choice, and in fact has persuaded us not to change it at all for the time being. Look at this graph of energy use per night for all 4 of our holiday accommodation units.
Beech Lodge, the brown squares, is pretty much indistinguishable from the other lodges in its energy use per night, even though it sleeps the most people (up to 8). In fact, Otter cottage consistently uses more energy than any of the lodges, even in the summer, even though it only sleeps 4.
And when you look at the energy use per guest per night, you see that even in summer, when most of the energy use will be for water, rather than heating, Beech Lodge with its electric shower (blue diamond now) is no worse than the other lodges. And in the winter, it’s arguably better.
That’s probably because more people are sharing the winter heating component in the larger lodge. And that’s probably also part of the reason that Otter Cottage energy use per guest night soars in the winter. The cottage attracts more couples than families, and its conventional stone construction makes it harder to heat.
There are some other excuses. Otter cottage electricity supply runs the shared washing machine and also an always-on pump. Nevertheless, having now seen Otter Cottage’s rising winter consumption we’ll be looking for ways to reduce it. Solar hot water, planned for this spring, would probably be good here – it would run the bath and basin (and probably the shower too as there are fewer guests to service).
And we have some other ideas for making the space heating more efficient – but that’s for another post.