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PIV vs Dehumidifier vs Heating: What Will Condensation Cost You This Winter?
PIV vs dehumidifier vs heating. Compare 2026/27 running costs and learn which approach could help tackle condensation and mould in your home.
Ian MurrayEnergy prices are increasing again this autumn, just as millions of households start thinking about turning their heating back on. Ofgem has confirmed that the energy price cap will rise from 1 October 2026, taking the typical annual household figure from £1,663 to £1,723. The average electricity unit rate will increase to 26.32p per kWh, while gas will rise to 7.97p per kWh.
For homeowners already worried about condensation and mould, it raises an interesting question. What is actually the most cost-effective way to deal with excess moisture this winter? Should you turn the heating up, run a dehumidifier or tackle the underlying ventilation problem with a PIV unit?
They all work differently, so it isn't simply a case of choosing whichever appliance costs the least to run. With the new October energy rates now confirmed, we are going to give you some examples and help you figure out the best option.
Can You Stop Condensation By Turning Up The Heating?
Turning up the heating is probably one of the most common pieces of advice given to people struggling with condensation. There is some logic behind it. Warmer walls, windows and other surfaces are less likely to become cold enough for water vapour to condense upon them.
The main problem with that is heating doesn't actually remove the moisture from your home. Cooking, showering, drying clothes and simply living in the property continually add moisture to the indoor air. If there isn't adequate ventilation, that moisture remains inside the property.
Turning up the thermostat may therefore reduce visible condensation in some circumstances, but it doesn't necessarily address why humidity levels are high in the first place.
It can also become an expensive approach if you are heating the whole house for longer simply to keep surfaces warm.
What About Running A Dehumidifier?
Dehumidifiers take a completely different approach. They draw humid air into the appliance, remove moisture and release drier air back into the room.
They can be extremely useful, particularly for drying clothes, dealing with temporary increases in humidity or targeting moisture within a particular room. However, running one every day comes with an electricity cost.
Take a hypothetical 250W domestic dehumidifier running for eight hours per day. At the new October electricity rate of 26.32p per kWh, it would use around 2kWh of electricity each day. That's approximately 53p per day or around £16 per month. Run it every day for six months and the electricity cost would be approximately £95.
Of course, that's only an example. Different dehumidifiers use different amounts of electricity and some will operate for considerably longer or shorter periods.
There's another important distinction too. A dehumidifier removes moisture from the air already inside your home. It doesn't provide fresh-air ventilation throughout the property.
How Much Does A PIV Unit Cost To Run?
Positive Input Ventilation works differently again. Rather than waiting for moisture to build up before removing it, a PIV unit continually introduces filtered air into the property. This helps displace stale, moisture-laden air and creates a continuous movement of air throughout the home.
PIV units are designed to operate continuously and use relatively small amounts of electricity to power the fan. For example, the Nuaire Drimaster ECO has a standard fan consumption ranging from approximately 1.6W to 17W depending on the airflow setting and operating conditions.
Even if we calculate the running cost using 17W continuously, the system would consume approximately 149kWh of electricity over an entire year. At 26.32p per kWh, that works out at approximately £39 per year for the fan.
Because PIV units adjust their operation according to the property and system settings, actual fan running costs can be lower.
What About The Heater On A Heated PIV Unit?
This is where running cost comparisons need a little more explanation.
At ClearAIR, one of our most popular PIV installations is the Nuaire Drimaster ECO Heated system. It incorporates a heater designed to temper the incoming air during colder conditions.
That does not mean the heater is running continuously.
The fan operates throughout the year, while the heater operates when required according to temperature conditions and the way the system has been configured.
This means there isn't one meaningful annual heater running cost that applies to every home. A property experiencing colder loft temperatures will require different heater usage to another property experiencing milder conditions.
It is worth remembering that the purpose of the heater isn't to heat your home either. It simply tempers the incoming air to make the PIV system more comfortable during colder weather. The air coming in from your loft space can be a bit chilly.
PIV vs Dehumidifier vs Heating
The biggest mistake is treating these as three different products designed to do exactly the same job.
They aren't.
PIV unit
Introduces filtered fresh air and helps displace humid, stale air
Whole-house ventilation and long-term condensation control
Dehumidifier
Extracts moisture from existing indoor air
Targeted or temporary humidity reduction
Heating
Raises air and surface temperatures
Heating the home and reducing cold surfaces
There will be properties where a combination of these approaches makes sense.
A dehumidifier can be particularly useful when drying washing indoors. Adequate heating is obviously essential during winter. But neither replaces the need for effective ventilation if poor airflow is contributing to persistent condensation throughout the property.
Why Does Condensation Keep Coming Back?
This is the important bit. If you wipe condensation from the windows every morning and it returns the following day, the moisture hasn't suddenly appeared overnight. Your home is continually producing it.
A family showering, cooking, washing clothes and spending time indoors can introduce a significant amount of moisture into the property every day.
Without somewhere for that moisture to go, humidity rises. Once the humid air reaches colder windows, walls and other surfaces, condensation can form.
This is why simply cleaning mould, wiping windows or turning the heating up doesn't always provide a long-term solution. You are just papering over the cracks, it will keep coming back and keep causing problems
How Does A PIV System Help With Condensation?
A loft-mounted PIV system draws air from the loft space, filters it and gently introduces it into the property through a ceiling diffuser.
This creates a slight positive pressure within the home and encourages stale, humid air to escape through natural leakage points and existing ventilation routes. Instead of treating one bedroom or continually collecting water from the air, the PIV unit provides continuous whole-house ventilation.
For suitable properties, this can help reduce excessive humidity, condensation and the conditions that allow black mould to develop.
Is A PIV Unit Cheaper Than A Dehumidifier?
Looking purely at fan electricity consumption, a PIV unit can be considerably cheaper to operate than running a typical domestic dehumidifier for several hours every day. Using our examples, a 17W PIV fan running continuously would cost approximately £39 per year at the October 2026 electricity rate.
A 250W dehumidifier operating for eight hours every day would cost approximately £191 over the same 12-month period. But we wouldn't recommend choosing between the two purely on those numbers.
A dehumidifier and a PIV system perform different functions. The important question is why your property has excessive humidity in the first place and which solution is appropriate for the problem.
When Should You Consider A PIV Installation?
Occasional condensation doesn't necessarily mean you need a PIV unit. However, persistent problems throughout the property can indicate that the existing ventilation isn't coping with the amount of moisture being generated.
Some of the common signs we see include:
- Windows regularly covered in condensation during the morning
- Recurring black mould around windows, ceilings or external walls
- Bedrooms that feel particularly stuffy
- Musty smells within the property
- Condensation returning despite regularly opening windows
If these problems are happening throughout the home rather than in one isolated area, it may be worth looking at the property's overall ventilation.
“Great service from start to finish. The PIV system was installed quickly and professionally, and the installer was punctual, polite and explained everything clearly. Communication was very good throughout the process. As a landlord I really appreciate reliable contractors and would happily recommend this company to others.”
“Second to none. From all our questions about the process (which were answered swiftly, leaving us in no doubt), to installation (the engineer was friendly, professional, worked fast, and left zero mess), we were impressed. We weren't expecting to see a difference so quickly, but since the very first day we haven't had a single drop of condensation, and the air in our house feels fresh. We can't recommend these guys enough, and we have been recommending them to everyone!”
“Would highly recommend. We had a PIV fitted to help with condensation in the house. Steven was very helpful and knowledgeable. Jonny was great when fitting the PIV. Quick, no mess and answered any questions we had.”
“I highly appreciate the services we got from Clear air PIV installations. The communication and advise provided from start to finish was very pleasant. Happy I have installed a PIV system and am seeing the benefit. Thanks to the team.”
“From the beginning Clear Air PIV were really helpful and clear in explaining what needed to be done talked through everything before starting any actual work. The installation itself was very clean and the electrician was extremely friendly. Overall I am happy and I would not hesitate to recommend them to anyone.”
“This was a great service right from the initial phone call. The communication was there all the way through and the knowledge of the install and product was obvious from the start. They asked key questions about the house to ensure that this product could be installed, and when the work was carried out it was done quickly, cleanly and when they said it would. No fuss and no issues. The product is also good. It's quiet and it works. I would definitely recommend ClearAIR PIV to anyone.”
“Fully recommend, service and communication was excellent. Implementation spotless and we are getting no condensation, even in the coldest months.”
“Would highly recommend!! Fast and professional installation, competitively priced. The PIV is working well.... should have had it done ages ago!! Well worth the outlay”
“Had a piv system installed by clearAir Piv. Brilliant company to deal with. They were clean and tidy. A pleasure to deal with and would recommend to anyone. Hopefully this system solves our condensation problems.”
“From initial enquiry to competion of fitting of VIP unit I have nothing but praise for this firm. Communication from Steven was always prompt and information given was clear and concise. No "hard sell" just good advice. Cameron fitted the unit and completed full electrical check. He was also very pleasant, got on with the job and was able to answer any queries. He also left no mess and completed the work in a few hours. Early days but the unit appears to be doing its job well. Absolutely no condensation from day one. Can completely recommend this firm.”
“Highly recommend. Fantastic team”
“The service that we received from ClearAir PIV and Steven himself has been excellent. We have been looking into PIV systems for a while as we have had such a problem with condensation on our bedroom windows. As soon as the temperature begins to drop each year the windows are covered. It has ruined the decor around the windows and caused mould to grow on the frames. Having spoken to Steven on the phone I could tell had specialist knowledge in the area. There was no hard sell, just advice. I got him booked in the same week to fit an Nuaire PIV and I’m so glad we did. Fitting was done quickly and cleanly by John who was friendly, well presented and very knowledgeable and experience in ventilation systems. Steven came too to give advice on another issue we had discussed on the phone. Result: NO MORE CONDENSATION!!! I thought it might take a few days to clear the moisture, but the next morning we checked the windows when they would normally be soaked and… nothing! And nothing since! So happy! I’d read in some reviews of the PIV systems that they were noisy and made the landing cold. This is not my experience. I honestly can’t hear it and although the landing may be ever so slightly cooler, the overall temp of the house isn’t effected and it’s not anything I’m concerned about.”
“Brilliant from start to finish. We couldn’t be happier with the professionalism showed by Steve and his team and would definitely recommend to anyone looking to get a PIV system installed.”
“I’ve just had installed a piv system. Steven and his team were a delight to deal with. Professional from start to finish. All our mould we were so worried about previously has now disappeared. Thanks again.”
“Knowledgeable, easy to deal with, very happy with the results. Would definitely recommend!”
“I recently had a new PIV unit installed by ClearAIR and the experience was excellent from start to finish. Steven and his team were professional, efficient, and a pleasure to deal with throughout the entire process. Since the installation, our mould problems have completely resolved and the improvement in air quality has been remarkable. ClearAIR delivered outstanding service and results, and I would not hesitate to recommend them.”
“Just had a new PIV unit installed by ClearAIR and I can only say positive things. The whole team from Steven to his employees were amazing to work with, since the instalment all our mould has disappeared and I can’t thank the team enough.I highly recommend ClearAIR as they were worth every penny.”
“Would highly appreciated Steven at clear air piv. From start to finish he was so helpful and kept us upto date with the installation. We've noticed a massive difference since. Thank you for a great service”
“Excellent Service and Results! I recently had a new PIV system installed in my home, and I couldn't be happier with the outcome. Communication with Steven was excellent from start to finish — he responded immediately to any queries and kept me informed throughout the entire process. The installation itself was smooth and professional. Since having the system installed, I’ve had no issues with mould or condensation — a huge improvement! I would highly recommend Steven and his company, CLEARAIR PIV Ltd. Reliable, efficient, and effective service.”
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“Fantastic service came on time well early even re solved a problem we have had for years removing our damp highly recommend steven at clear air”
“Couldn’t recommend Steven enough. From start to finish the communication was amazing and everything was explained so clearly. He was professional, efficient, and made the whole process completely stress-free. The quality of work is outstanding, and it’s clear he really takes pride in what he does. I wouldn’t hesitate to recommend Steven at Clear Air PIV to anyone looking for a reliable and trustworthy service.”
“Wasn’t sure what I needed, and Steven recommended a product that has transformed the condensation in our house. 100% recommend”
“Really great service from Steven and the team. Couldn’t recommend more highly”
“We had a PIV unit installed in one of our rental properties. The team were very helpful and the price was really good!”
“Had a PIV unit installed from these and I am really happy with the service and the price was really good”
“Very impressed with Steven and his team. From the get go of filling out the questionnaire online, Steven contacted me and booked me in for a visit. He was polite and there was no pushy sales pitch, just straight talking and down to earth. I’d recommend anyone who’s considering having a PIV unit to contact Steven.”
“I Had a PIV unit installed and was very happy with the service.”
PIV Installations From ClearAIR
At ClearAIR, we specialise in loft-mounted domestic PIV installations designed to improve airflow and help tackle condensation, mould and poor indoor air quality.
We currently offer two PIV units:
The Vent-Axia PIV system costs £945 fully supplied and installed. Our premium Nuaire Drimaster ECO Heated PIV system costs £1,045 fully supplied and installed.
Where the existing electrical installation requires a Type A RCD fused spur for the PIV unit, this can be installed for an additional £75.
Before recommending a PIV installation, we'll ask for some basic information about your home along with photographs of the loft access, loft space and fuse board. This helps us establish whether a loft-mounted PIV system is suitable for the property.
Frequently Asked Questions
How much does a PIV unit cost to run?
Running costs depend on the PIV unit and its settings. As an example, a 17W PIV fan running continuously would use approximately 149kWh per year. At the October 2026 electricity rate of 26.32p per kWh, that would cost around £39 annually for the fan.
Is a PIV cheaper to run than a dehumidifier?
It can be. PIV fans are designed for continuous low-energy operation, whereas a domestic dehumidifier will typically use considerably more electricity while operating. However, they perform different functions and shouldn't be compared on electricity consumption alone.
Is it cheaper to use a dehumidifier or turn the heating up?
There isn't a universal answer because heating costs depend on the property, heating system, insulation and thermostat settings. A dehumidifier removes moisture from indoor air, whereas heating primarily increases the temperature of the air and surfaces.
Does heating stop condensation?
Heating can help reduce condensation by warming cold surfaces, but it doesn't remove the moisture being generated inside your home. Effective ventilation remains important.
Should a PIV unit run continuously?
Yes. PIV units are generally designed to operate continuously at low power, providing a consistent supply of filtered air throughout the property.
Does a heated PIV cost more to run?
Yes. When the heater is operating it will use additional electricity. However, the heater doesn't run continuously and its actual usage will depend on temperature conditions and system settings.
How much does a PIV installation cost?
ClearAIR currently charges £945 fully supplied and installed for a Vent-Axia PIV system and £1,045 for a Nuaire Drimaster ECO Heated PIV system. If a Type A RCD fused spur is required, this costs an additional £75.
Get Your Home Ready For Winter
With energy prices rising again from October, nobody wants to spend more than necessary trying to keep condensation under control.
If you're continually running a dehumidifier, wiping down windows or turning the heating higher only to find condensation returning, it may be time to look at why moisture is becoming trapped inside your home.
For suitable properties, a professionally installed PIV unit provides continuous whole-house ventilation using a low-energy fan.
If you're experiencing persistent condensation, recurring black mould or poor indoor air quality, speak to ClearAIR about whether a PIV installation could be suitable for your home.