You need to consider that some walls may contain water pipes. Not having those warmed up sufficiently could lead to a bursted pipe, which could lead to significant damage.
Also keep in mind that keeping your house below 15C can cause damp issues.
MMMMM Mold.
Whats the min temp to be responsible but also keep the central heat waste to a minimum?
Cautionary tale:
For us it was trial and error. We thought we were doing pretty well by keeping track of the weather and balancing the whole house heating vs single room. Until we had a snap freeze that plummeted the temps overnight to an obscene degree. We were comfortably warm in our bedroom as all the pipes in the kitchen and bathroom were bursting.
10’s of thousands of dollars in demolition and reconstruction later we have decided that in this instance it’s better to waste some small amount of energy keeping the whole house heated rather than risking another catastrophic failure.
Your mileage may vary.
Fwiw, most modern thermostats have an emergency failsafe temp setting that will always turn the heater on when reached, even if inadvertently set lower by mistake. Saved my bacon in a rental once.
As a side note, if you for some reason turn off the central heating entirely and just use space heaters, then the failsafe will do no good.
Most central heating solutions waste some energy when idling, so one might be tempted to turn them off. Please be careful when doing this.
This was a solid case of “if it ain’t broke don’t fix it” the thermostat and heating system in question was from the 60’s or 70’s and had served us with no issues for as long as we had been there. Hindsight 20/20 and all that jazz.
Fwiw there is low power heat tape you can buy to run along pipes to keep then from freezing. Had this on a pipe that ran through an attic and would freeze when the outside temp got extreme, despite heating the house.
Generally, 55-60 Fahrenheit (13-16 C) should be safe. If you have mild winters and a house layout that isn’t too spread out, you may be able to set it as low as 45 F (7 C).
Winter can be quite harsh where I live, and 16°C is the recommended minimum temperature.
That depends on the plumbing and how cold for how long it is in the area. Also, going too cold isn’t good on the house, either. Drywall and wood don’t like all the temp swings, either.
55F / 13C
Please consider moisture (=mold) depending on humidity levels where you are. For example if you have one warm room the air will cool on the uninsulated interior walls to the next room, cooler air can not contain the same amount of humidity so this will condensate on (or in!) your walls. This is a good way to grow mold and get all kinds of expensive health issues.
Adding to what others have mentioned, you probably don’t use the same type/source of heat for the full house. A typical space heater is resistive heat, which is simply turning electrical energy into heat energy (at 100% efficiency). Your central heat could be a Gas-powered furnace (converting chemical energy to heat energy at ~90% efficiency), heat pump (converting electrical energy to heat at 300+% efficiency), or a few other options.
In my area, gas is much cheaper per joule than electricity. it ends up being the same price to heat the entire place with gas as it would be to heat just a room with an electric space heater. If I were to use a kerosene space heater, or a heat pump, or whatever else, then the numbers would change.
Yes, basic math says it uses less energy to heat a smaller area than a larger one. But that’s assuming the same type, cost per unit, and efficiency. This is unlikely unless you have the worst option on both (resistive electric heat)
Lovely reply; this is not the simplest answer but it’s the truth.
Buying gas is way cheaper than buying electricity; however, if your electric grid contains any significant portion of carbon-zero producers (hydro, nuclear, solar, wind), using electric space heater will emit less CO2 than gas furnace, for the same amount of heating. If you care at all about CO2 that is. This is the main reason why burner heaters have been so difficult to replace - we thought we could price our way out, let market forces pull us gently into a renewable future without having to make personal sacrifices, but gas is just so much cheaper it’s tough to give up.
An electric heat pump will just about break even on cost with gas, while giving even greater CO2 savings. Annoyingly, a gas-powered heat pump will still be cheaper.
You may not use the space, but you likely have water lines that can’t handle freezing temps, and other electronics/appliances that assume living space (non condensing humidity being important)
Now, setting your thermostat lower and only heating the room you’re in? Maybe. Whole house systems are damn efficient, so if you’re moving around the house with the heater, that’s a no go, but if you hang out in one closed door room, it’s an experiment you might want to try.
Expect the bathroom to be colder than you’d like if you’ve spent the day in your bedroom/office.
I actually think its really good for sleep too for it to be a bit hibernation-level chilly in an ambient sense.
My muscles clench up when I try that, which makes my back problems worse.
Is there a treatment [dont mean medicine] or discussion on this topic you would recommend, thats interesting. Something, something, muscle spindle fibres?
Depends on the efficiency of the heater but, as long as the space is enclosed, almost certainly yes.
Keep in mind that your interior walls aren’t insulated, so you’ll lose some of your heat to other rooms, probably causing higher-than-expected usage. Along with the bursted pipes, which have already been mentioned, I’d be also concerned about interior temperature gradients and condensation, and resultant mold and mildew issues.
As many people said, it depends on your system. Some highly efficient central heating can have greater than 100% efficiency, so a space heater MIGHT be more expensive than the central heating unit.
Typically a better way to keep the cost lower is to set your home’s thermostat to a lower, but still home safe number, like ~55 degrees F (~15 degrees C) and then use a smaller space heater in the room you are using, or just bundle up with hot tea/blankets/sweaters, but allowing your house to get much colder than that might not be good for your appliances, furniture, pipes, etc.
Depending on how much you want to invest, you can upgrade to a mini-split HVAC system and keep each zone of your home at a different temperature based on needs, and it can be far more efficient (and safer) than managing space heaters.
Some highly efficient central heating can have greater than 100% efficiency
How’s that supposed to work? What values are being compared? As a general engineering principle, I thought all transformations include at least a little loss.
Because in the most efficient systems, you aren’t creating heat, you’re moving heat.
Just as a made up example - with a space heater, you could get 1000 watts of heat from 1000 watts of electricity, or you can move 1500 watts of heat with 1000 watts of electricity with a heat pump.
It’s pretty neat.
The heat pump in my home has an SCOP of 4.9 under perfect conditions and ~3.5 under normal conditions, which means 1kW of electricity in equals 3.5-4.9kW of heat out.
Ohh okay, well yeah if you count heat pumps that’s another story. I was only thinking in terms of energy generation (usually from burning something or electrical resistance).
Thanks for the video, I think I saw that channel once and it was interesting so I look forward to watching it later. It’s been a long time since my thermochem course so it’ll be good to revisit some concepts.
Here is an alternative Piped link(s):
https://piped.video/7J52mDjZzto
Piped is a privacy-respecting open-source alternative frontend to YouTube.
I’m open-source; check me out at GitHub.
If they are speaking about heat pumps then they are technically correct. A heat pump uses energy to move heat from one location to another instead of converting heat from form to form. It’s the conversion that causes inefficiency.
I’m not nearly smart enough to properly explain the physics of it but there are plenty of articles and YouTube videos available if you want to go down that rabbit hole.
Keep all rooms safely above freezing, +10 Celsius/ +50F and only heat one room warmer. Calculate the power/fuel you would use then and compare to full central heating (it can be different for every location). Generally speaking in many countries running something that heats or cooles rooms with electricity 24/7 will make your power bill skyrocket. Damage to property caused by the cold like burst pipes and other stuff can certainly cost you any savings made and more.
All these people talking about mould and freezing pipes, and so on, and I as an Aussie am deciding I’m totally out of my depth. An observation; We get only a few days of snow in winter every year. Our pipes don’t freeze, our houses don’t get mould from this. If you aren’t in a cold enough to freeze the pipes type place, perhaps do what Aussies do and heat only one room in the house, it’s fine.
