Thermostat Turn-Down Savings Calculator
A small change to your thermostat setting is one of the easiest ways to cut your heating costs without any upfront spend or disruption. Enter your current annual bill and how many degrees you're considering turning it down to see a rough estimate of the saving.
Estimate your thermostat turn-down savings
Enter your current annual heating bill and how many degrees you plan to turn it down.
Turning your thermostat down by 1°C could save you approximately:
£96.00 per year
That's roughly a 8% reduction on your current bill. This is a rule-of-thumb estimate — actual savings depend on your property, the weather and your heating system.
Recommended products
A few well-reviewed thermostats and heating controls to consider.
- WiFi
£159.99
Pros
- Controls boiler heating and hot water from the app
- Works with Alexa, Siri and Google Assistant
- Geofencing and open-window detection help cut bills
Cons
- Subscription needed to unlock some advanced features
- DIY install requires access to the boiler wiring
- WiFi
£199.69
Pros
- Dual zone control for separate heating and hot water schedules
- Works with Amazon Alexa, Google Home and IFTTT
- Expandable with room thermostats and smart radiator valves
Cons
- App can be fiddly to set up multi-zone schedules initially
£138.29
Pros
- Voice control via Alexa, Google Assistant and Apple HomeKit
- Auto-adapt algorithm learns your home heating pattern
- Sleek minimal design with a companion smartphone app
Cons
- Compatible with individual boiler systems only, not underfloor loops
Frequently asked questions
How much can I really save by turning my thermostat down by 1°C?
The commonly-cited rule of thumb from UK energy advice is a saving of roughly 8-10% on your heating bill for each degree you turn the thermostat down, though this is a broad estimate rather than a precise figure for every home.
Will turning the thermostat down make my home uncomfortably cold?
Most people don't notice much difference after turning the thermostat down by just 1°C, since it's a fairly small change, though it's worth adjusting gradually if you're sensitive to temperature or have vulnerable household members.
Does this saving apply to gas and electric heating equally?
The percentage saving broadly applies regardless of fuel type, since it reflects reduced overall heat demand, but the actual pound amount you save depends on your unit price for gas or electricity and how efficient your heating system is.
Why does the calculator cap savings at 30%?
Turning a thermostat down by a large number of degrees doesn't keep delivering savings at the same steady rate, since at some point a home simply isn't being heated meaningfully at all, so the estimate is capped to avoid an unrealistic result — this is a rule-of-thumb tool, not a precise energy model.
How this calculator works
The calculator estimates savings by taking into account your home’s size (measured in square metres), its insulation level (rated on a scale of 1-5, with 1 being poorly insulated and 5 being highly efficient), and your current thermostat setting. It then applies an average heat loss factor based on this information – a typical loss of around 25W per square metre for a standard brick built house in the UK, but this can vary greatly depending on factors like double glazing and age of the property.
The calculator multiplies this heat loss factor by your chosen thermostat setting (expressed in degrees Celsius). The result provides an approximate annual heating cost saving, based on average UK energy prices. It’s important to note that this is an estimate; actual savings will depend on your individual usage patterns, external weather conditions and the efficiency of your boiler or heating system.
Insulation Levels & Typical Heat Loss
- **1-2 Insulation:** Significant heat loss – expect a large percentage of your energy to be lost through walls, roof and windows. Consider upgrading insulation for greater savings.
- **3-4 Insulation:** Moderate heat loss – typical for many older UK homes. Improving insulation can significantly reduce bills.
- **5 Insulation:** Excellent heat retention – minimal heat loss, ideal for new builds or properties with high levels of existing insulation. Double glazing is highly recommended.
- Average Heat Loss: A well-insulated modern home (rated 4 or 5) might experience a heat loss of around 18W per square metre. Older homes (rated 1 or 2) could lose up to 40W per square metre.
- External Walls: Typically account for 30-40% of heat loss in a typical UK home. Consider external wall insulation if you are looking to improve your energy efficiency.
- Windows & Doors: Older, single-glazed windows and poorly sealed doors can significantly increase heat loss. Replacing with double or triple-glazed options offers substantial savings.
- Roof Insulation: A significant source of heat loss, especially in older homes. Adding loft insulation (mineral wool is a common choice) can dramatically reduce this loss.
Worked example: Reducing your thermostat by 1 degree
Let’s say you have a semi-detached house in Manchester measuring 120 square metres with an insulation rating of 3. You currently set your thermostat at 21°C. Using the calculator, inputting these figures yields an estimated annual heating cost saving of approximately £360 – based on current average UK energy prices (as of October 2024).
Reducing your thermostat by just one degree to 20°C would further reduce this saving to around £288 per year. This demonstrates the significant impact even small adjustments can have, particularly when combined with improving your home’s insulation. Remember that these figures are based on averages; your actual savings may vary.
More questions answered
What does 'insulation rating' mean?
The insulation rating is a subjective measure of how well your home retains heat. 1 represents poorly insulated older properties, while 5 indicates very good insulation found in newer builds or those with significant upgrades like cavity wall insulation. It’s a relative scale to allow you to estimate the potential savings based on your property's current state.
How accurate are these calculations?
This calculator provides an *estimate* based on averages and assumptions. Actual energy consumption will vary greatly depending on your specific circumstances, including usage habits, weather conditions, boiler efficiency, and the quality of your insulation. Use it as a starting point for understanding potential savings.
What if my home is very old?
Older homes often have significant heat loss due to poor insulation and drafty windows. You’ll likely need to reduce your thermostat setting further than suggested by the calculator to achieve substantial savings. Consider external wall insulation or draught-proofing measures.
Does this calculator account for different boiler types?
No, the calculator doesn't directly factor in boiler efficiency. However, a more efficient boiler will naturally reduce your overall energy consumption and improve your savings regardless of thermostat setting. Consider upgrading to an A-rated condensing boiler.
What if I have solar panels?
The calculator does not account for solar panel generation. If you generate electricity from solar panels, your actual heating costs will be lower than the estimated savings – this could lead to positive or even net energy savings!
Can I use this calculator if my home is a flat?
While this calculator is primarily designed for houses, you can still get an estimate. However, your heat loss will likely be higher due to the shared walls and potential for drafts. Consider the insulation of your neighbours' properties when estimating.
How do I interpret the result?
The result represents an *estimated* annual saving on your heating bill based on the inputs you provided. It’s a useful benchmark for comparing different thermostat settings and considering energy-saving improvements.
What if I enter incorrect values?
The accuracy of the results depends entirely on the accuracy of the input data. Be as honest and realistic as possible when entering your home's size, insulation rating, and thermostat setting to get a more reliable estimate.
Can this calculator help me choose a new thermostat?
While the calculator doesn’t directly recommend specific thermostats, it can help you understand how much you could save by reducing your thermostat setting. Consider smart thermostats which allow for precise temperature control and scheduling to maximize savings.
What are some other ways to reduce my heating bills besides lowering the thermostat?
Besides adjusting your thermostat, consider draught-proofing around windows and doors with weather stripping or tape, investing in a hot water tank insulation jacket, and regularly servicing your boiler to ensure it’s running efficiently. Small changes add up over time!