Several years ago, I was amazed (and quite repulsed) to read about a café in Paris which supposedly had an open terrace and kept it heated throughout winter, with tropical plants in pots and matching décor and guests. It sounded to me a bit like a golden toilet bowl, or a personal shopping assistant, or drag racing – roughly equally senseless. I was caught unprepared by the idea that it might appeal to people, but didn’t think much about it at the time.
In the short years since then and now, these heated terraces have stopped being a foreign curiosity and have instead become a frequent sight in the café-inundated parts of the city. Cafés, restaurants, fast food stands, pizzerias – they all have people sitting in jackets and scarves, sipping their tea and coffee, chatting away about one thing or another. Heated terraces have become so pervasive that there are café catalogues which list them as a category and tick it off for the cafés which have one. Some places promote them as their unique selling point: “[…] It also has an envied feature of a heated open air roof top terrace […] makes this bar unique amongst other bars in the area. With a wide selection of…” Then they go on about various kinds of fabulous drinks, the atmosphere, work hours, special programs and so on.
People being people, they have a great many things on their minds keeping their minds off of even more other things. I believe this is a critical requirement for the success of outdoor heaters (doesn’t “outdoor heater” sound like an oxymoron?). A public sensitive to e.g. heavy dependence on foreign energy importing (e.g. in Croatia) might not find the prospect of idly chatting under 10 kilowatt heaters very appealing. If the handful of people sitting on the terrace in the picture spent an hour and a half there, they would have spent enough energy to keep a room of their home heated during the entire day. These last few winters all eyes were turned to Ukraine and Russia to see if natural gas would flow and if Europe would have heating. Then there is a lot of talk about thermal isolation of buildings: big national and international plans are written up to set up and enforce building energy efficiency standards, builders use thick, specialized isolation, space-technology multilayered noble gas-filled windows etc. But then people go and squander any savings on a coffee break after work because they don’t think about what they are doing. Ask them: it is not that they don’t care – some surely don’t, but I would say it is quite likely that they are there simply because the problem hasn’t been brought to their attention.
In brief, the efficiency equivalent of heating an open terrace is using a fork to eat soup. Please do tell your friends about it: they deserve a chance to make informed decision themselves. You do, too.