Some thermostats can be controlled only by the owners, say via an app that they don’t share with a sitter. I sat a home like that, which they mentioned in the welcome guide — said, let us know if you need the thermostat adjusted. I didn’t care at the time, because it was during nice weather. If it weren’t, I would avoid such sits, because I don’t want to be asking every time I want the thermostat adjusted.
That is a pretty fascinating “modern” question - I had a sit this summer where the house was horribly hot and I could not turn on the air conditioning. I finally realized the host had to do it remotely with her app, which she did. Given that this is becoming a much more common issue with “remote control” utilities at the least this should become a topic of discussion in the video call. I would pass up a sit where the host would not allow me to control the temperature.
Uk has variable weather not to mention the OP may come from a warmer climate. Regardless it’s all about hospitality not penny pinching.
The HO is being inhospitable and should care about your comfort over being a Scrooge.
In fact, there was a thread about this happening to a sitter a while ago.
It weakens your immune system and in healthy pets and people make you more susceptible to the common cold and flu like symptoms. I stand by what I said. Thank you for your comment though.
So well thought out! Thank you.
I’m glad you say you’ve been living in the UK for 20 years, or my answer would be slightly different, ie you need to have clothes for all seasons in the UK, as the temperature changes fast. We use a blanket on the sofa before putting the heating on in our own home 
.
In your case though, living here 20 years, I’m not sure why you asked the owners in the first place, you can find out how to use the controller online for almost all brands nowadays.
If it were us, and the temp dropped to the point we needed heat, we would have just put the heating on for a couple of hours, without asking at all because owners will know that we/you living in the UK for 20years wouldn’t have put it on unless we needed to, and just told them when they returned that there was a couple of days when the temp dropped & we popped the heating on, if that was the case.
September weather in the UK is not hazardous to anyone’s health, unless they are extremely frail. It’s been a few degrees chillier the last few days than the previous weeks, that’s all that has happened. Heating is almost a national obsession in the UK, because energy costs are so high, off the scale for anyone from the USA. Some home owners won’t put on their central heating for several months yet.
No disrespect but that hardly seems likely. I live in a mild climate area of the US and pay $250 per month for utilities in the summer. That amount triples during the coldest months.
UK energy prices are higher than that?
Just curious.
Recent data from the Department for Energy Security and Net Zero and Carbon Brief reveal that UK households are now spending up to 40% more on energy than US households. The energy crisis, exacerbated by global events such as the post-COVID economic rebound and the conflict in Ukraine, has led to unprecedented increases in gas prices. These factors have pushed UK household energy costs to record highs, with predictions that the average household could face annual bills exceeding £3,500 by the end of the year.
In contrast, US households benefit from a more stable energy market and greater domestic energy production, which has helped mitigate extreme price hikes. The US Energy Information Administration (EIA) reports that the average American household spends around $1,500 annually on energy, significantly lower than their UK counterparts.
https://www.statista.com/statistics/263492/electricity-prices-in-selected-countries/
Domestic electricity prices in the UK are > twice those in the US.
I am extremely frugal with heating in my own home and therefore equally frugal when I house sit. Having said that, a home owner presenting as being mean, for no apparent reason, would put me off from taking a sit. If they perhaps explained that they were struggling to pay their bills, or that they were very environmentally conscious that would be a different matter.
I anticipated that the temperature would be dropping, at the start and end of the day, in the UK this month so I checked, before my arrival, that the homeowners had a hot water bottle and a throw for me to use if needed when sitting down.
I have had problems a couple of times with homes that were unbearably warm and I could not turn the heating down, I found that very unpleasant.
Yes, the temperatures in the UK can shift wildly from one day to the next. Honestly, I’m surprised you even asked, I’d never think to seek permission for something so basic.
They do sound rather petty… and apparently completely oblivious to what their boarding expenses etc would look like if you weren’t there.
Interesting proposal! I asked because I wasn’t shown how to use the heating and needed instructions, and also because it’s courteous and I simply assumed that it would be met with something along the lines of “of course you can!” That wasn’t the case as it turns out.
I have learnt my lesson. Yes, this is a new ‘modern’ issue and I partly raised this thread as I believe that this will happen time and time again to others. I think this thread might grow exponentially one day!
They are aware. They will ‘monitor’ the temperature and weather apparently. Lucky me 
Full disclosure - I have been offered the use of an electric spot heater if I really need it, in lieu of central heating. But I find this an inadequate response. Fine, it will heat the room I’m in but only one room at a time. The house has split heating and I only asked for one half to be heated - the areas that I will actually use. Again, thinking about saving energy and not needlessly heating the home. So…….wasting my courtesy it seems.
Electric heaters are often more expensive to use, so maybe they’re actually cheap and foolish.
British Houses are notoriously badly insulated, too.
Our old place you could have the heating on 24/7 and still be cold under a pile of blankets if you were in certain rooms, but the upstairs would be unbearable after 20 mins.
Our new house is much better thankfully and the doenstairs is warm, but even so, our bills are ridiculous. We keep the baseline temp at 18, which is the same for a lot of people in the uk, but if youre used to a higher baseline I cant imagine its much fun. if we had a sitter from warmer climes would definately tell them to turn up to 21!
This is unfortunate. How long is the sit, do you think you will be able to stick it out?
Its not ideal, but if you do want to stay may be worth buying a hot water bottle.
I would definately want to know if any host was frugal with heating. It could be a 5 star sit all around but being cold is horrible, and its not always possible to pack for all weathers.
Really hope they see reason