As September starts drawing to an end, the thought of switching my central heating back on for the first time in months sends shivers down my spine (and not just because it means it's getting cooler). I know exactly what that first bill is going to look like once the whole system is running for months on end.
My home office is the room I'm most anxious about. It's a small space with one slow radiator, and I'm in there five days a week, often for eight hours at a stretch. Heating the entire house just so one room reaches a comfortable working temperature has always felt wasteful. So before I turn the whole system back on this year, I wanted to test a simple idea: could a portable electric heater do the job instead, just for my office, and save me money in the process?
On paper it sounds like an easy win. In practice, it's more complicated than that. So rather than guess, I asked heating engineers and energy experts a straight question: is a portable heater ever a genuine replacement for central heating in one room, and what are the catches nobody mentions before you buy one?
Is it cheaper to use a portable heater than central heating for one room?
This is the question I most wanted answered, but it's not as straightforward as I'd first hoped.
"Electricity costs roughly three to four times more per unit than gas," explains George Penny, heating expert at The Solar Co. "Based on Ofgem's October to December 2026 price-cap rates, running a 2kW fan heater for five hours costs around £2.63 a day, compared with roughly 89p for the same heat from a modern gas boiler. Across a 92-day winter period, that's a difference of around £160." That figure alone nearly put me off the whole idea.
The maths changes though if you're heating one room instead of an empty house, which is exactly my situation. Ben Rawson, heating expert at Electric Radiators Direct, pointed me to a lower-wattage option better suited to a home office. "Running a lower-watt electric heater (500W) for four hours a day costs £1.04," he told me. "That's considerably less than it would cost to run the central heating over the same period." That was closer to the number I'd been hoping for.
So the answer, I realised, depends entirely on wattage and hours used. A 2kW heater running all day would be a false economy for me, but a low-wattage heater used only while I'm actually in the room looks far more promising. I checked my own central heating running costs per hour to see how the numbers stacked up against my heater, and the comparison was enough to convince me to keep testing the device rather than send it back.
George Penny is Director of The Solar Co. He's passionate about leading the UK's transition to efficient, reliable renewable heating solutions for households and businesses alike.
Ben Rawson is Operations Director at Ignition Group, home of Electric Radiators Direct and Ecostrad. With experience in product compliance and testing, he's a leading voice on electric heating in the UK.
When is a portable heater a sensible replacement, and when isn't it?
Having the numbers in front of me was reassuring, but what I actually needed to know was whether my specific setup made sense for using a portable heater over central heating.
Ben Rawson thinks a home office is one of the better use cases: "If you have a separate home office, you won't need to warm your bedrooms and other living spaces during the day while you work," he told me. "Having a portable heater in your working space means you can leave your central heating thermostat alone and focus on heating the specific area you'll be spending most of your time in. This is also known as zoned heating."
Matthew Powell, founder of WarmZilla, agreed in principle, but suggested checking whether I needed a portable heater at all. "Before committing, check what your existing heating controls can achieve, because suitable zoning may let you heat the room economically," he explains. The best way to achieve this might be through smart heating controls, like a smart thermostat or thermostatic radiator valves on individual rooms, rather than buying a separate appliance.
He also added a word of caution about relying solely on a plug-in heat source: "The arrangement becomes less convincing when the room loses heat quickly or other household members also need warm rooms."
That gave me pause for thought. My office is toasty enough while the electric heater is running, but single glazing and uninsulated stone walls mean the chill creeps back in fast once it's switched off, which isn't exactly the self-sufficient heating solution I'd pictured.
Matthew Powell is founder of WarmZilla, an online boiler and home services company based in Cardiff. Starting as a plumbing apprentice, he spent over 20 years building heating and plumbing businesses across the UK.
What type of heater suits a home office?
I'd already acquired a portable heater in the form of the Electrolux 2kW Digital Eco Oil-Free Radiator with Remote Control, so I wanted to know from the experts whether I'd picked well, or just picked what looked nice online.
Ben Rawson explained that "dry thermal electric radiators are usually branded as 'oil-free' as they use aluminium heating elements instead of liquid. This makes them highly responsive, reaching temperatures quickly for effective warmth. Plus, they're also really light and super practical for a smaller home office." That matched what I'd noticed already: mine heats up fast and is easy to move around if I want it nearer my desk on colder days.
Matthew Powell and Ben both agreed that traditional oil-filled radiators were arguably the strongest option for long desk sessions – as they're slower to warm up but hold heat particularly well after switching off. The experts also agreed that ceramic heaters were a fast way to heat a room, and infrared heaters were ideal for spot-heating one person rather than the whole space. Fan heaters were the only type of emitter nobody rated for a full working day, as they're too noisy and too quick to lose heat once off.
So while there are several types of radiator that would have worked, the oil-free model I'd already chosen turned out to be a solid pick.
My choice of heater was this 2kW oil-free radiator with digital thermostat, remote control, auto-off timer and overheat protection, suited to rooms up to 20m².
Another highly-rated option is this 2500W oil-filled radiator with 11 heating fins, adjustable thermostat, 3 heat settings, a 24-hour timer and full tip-over safety protection.
The downsides to using a portable heater over central heating
My oil-free radiator had passed the cost and suitability test, but I still wanted to know if there were any possible downsides to relying on it to heat my home office.
Matthew Powell was blunt about the main risk. "The concern is allowing the rest of the house to become persistently cold while keeping one room comfortable," he told me. "Moisture from everyday living can condense on colder surfaces, particularly in rooms with poor ventilation, increasing the risk of mould."
Ben Gallizzi, energy expert at Uswitch, made the same point from a different angle. "Heating a single room does not necessarily address the temperature of the rest of the property," he said. "Relying on one heater as the only source of heat may leave other rooms colder than intended."
Neither of them told me to stop using the heater, but I am going to start opening a window for a few minutes each day, and I won't be switching the central heating off in the rest of the house entirely, just turning it down.
Ben Gallizzi is an energy expert at Uswitch, helping households understand and compare their gas and electricity costs. He specialises in breaking down complex tariff and running-cost data for consumers.
My final plan for staying warm without sacrificing other rooms
From the experts I spoke to, it's clear that a portable heater can save you money in a home office, but only in fairly specific conditions: you're the only person using it, the room is reasonably well-insulated, and you're not leaving it running all day out of habit.
For my own office, with its single glazing and uninsulated stone walls, that verdict comes with a caveat. The heater keeps me warm while I'm working, but I'm not switching off the central heating for the rest of the house, and I'll be keeping an eye on the room for any early signs of damp. It's a solid cost-saver for the right room – mine just isn't quite that room yet.
FAQs
Is it safe to leave a portable heater on all day in a home office?
Not unattended, according to every expert I spoke to. Ben Rawson was clear that heaters "should not be left running or unattended for long periods," and George Penny made the same point about keeping heaters away from anything flammable and switching them off whenever I leave the room. I've started turning mine off during lunch and at the end of the working day, rather than leaving it running from 9am to 5pm.
Will using a portable heater show up on my smart meter?
It should, and it's worth checking. A 2kW heater running for several hours a day is a noticeable, steady draw compared with the shorter bursts of a boiler cycling on and off, so if you have a smart meter, keeping an eye on it for a week is the easiest way to see what your own heater is actually costing you, rather than relying on averages.
Can I use a portable heater instead of central heating for more than one room?
Not sensibly, based on what I was told. Every expert I spoke to described this as a single-room solution at best. Once you're trying to heat more than one space, or a large or poorly insulated room, the running costs and the damp risk both increase, and central heating becomes the more sensible option again.
When you finally do decide it's time to turn the heating back on, it's worth running through this autumn central heating checklist to make sure everything's up to standard first. It only takes a few minutes, but catching a problem now is far better than discovering it on the first freezing night of the year.
