Positive Input Ventilation eliminates condensation and mould at source. Fully installed from £825, 7-year warranty, covering Manchester, Tameside, Stockport, Trafford, Oldham, Rochdale, Wigan, Bolton and Bury.
Positive Input Ventilation (PIV) is a whole-house ventilation strategy that works by gently but continuously pushing filtered, tempered air into a property. Unlike extract-only ventilation, which simply removes air from a single room, a PIV system creates a positive pressure throughout the entire building. This positive pressure forces stale, moisture-laden air out through normal gaps and leakage points, replacing it with fresh, drier air from outside or from the loft space.
The science is straightforward. Condensation forms when warm, moisture-saturated air comes into contact with a cold surface and the air can no longer hold its moisture in vapour form. In a poorly ventilated home, indoor relative humidity can routinely exceed 70-80%. At these levels, every cold wall, window frame and corner is a potential site for condensation and subsequent mould growth.
A PIV system running continuously reduces indoor relative humidity to levels where condensation cannot form. The airflow rate is low enough to be completely unnoticeable in daily life, yet consistent enough to maintain conditions unfavourable for mould throughout the year, including the high-risk winter months when heating cycles create extreme humidity spikes from cooking, bathing and breathing.
For Greater Manchester homes specifically, where older solid-walled terraced housing makes up a large proportion of the housing stock, PIV is often the most effective and cost-efficient solution available. The alternative, mechanical extract ventilation in every room, is considerably more disruptive and expensive to install correctly.
Fresh air is drawn from the loft, filtered, and pushed gently into your home through a single ceiling diffuser. This creates positive pressure that displaces stale, damp air out through gaps around windows and doors.
Installation typically takes two to three hours. Here is what happens on the day.
We assess the property size, type, existing ventilation and the nature of the damp or mould problem. We check loft access and measure available head height to determine the correct unit and duct configuration.
The PIV unit is mounted on a platform or bracket in the loft, clear of insulation. Loft units draw air from the roof space, which is naturally drier and slightly warmer than outdoor air, making it ideal for conditioning before supply.
A short insulated duct runs from the unit through the ceiling to a hallway diffuser, typically centrally located to distribute fresh air evenly. The diffuser sits flush with the ceiling and is almost invisible once fitted.
The unit is wired to a suitable supply circuit. Most units draw between 5W and 25W, comparable to a small LED light fitting. No major electrical works are required in a standard installation.
The unit is set to the appropriate flow rate for the property. Summer boost and winter settings are configured. We explain the system and leave contact details in case of any queries.
We follow up to confirm humidity levels have reduced and that mould has not returned. In most cases customers report a noticeable improvement in condensation within the first two to four weeks.
We install units from the leading UK ventilation manufacturers, all of which carry a 7-year manufacturer warranty. The specific unit recommended will depend on your property type, the severity of the condensation problem and your loft configuration.
The Drimaster Eco is one of the most widely installed PIV units in the UK. Available in heat-recovery (HC) and standard versions. Whisper-quiet, 7-year warranty and designed specifically for UK housing. Our most commonly recommended loft unit for standard terraced and semi-detached properties.
Vent-Axia's Lo-Carbon Kinetic range provides high-efficiency PIV performance with very low energy consumption. Available in loft and through-wall configurations, making it suitable for flats and maisonettes as well as houses. Particularly well suited to newer, well-insulated properties.
Envirovent's Energy Saver range is optimised for cost-conscious landlords and social housing providers. Highly reliable, very low running costs and straightforward to service. A strong choice where multiple properties need to be treated to a consistent standard.
All prices below are fully inclusive of supply, installation, commissioning and VAT. You receive a fixed price in writing before any work is carried out. There are no hidden extras.
| Installation Type | Suitable For | Starting Price | Warranty |
|---|---|---|---|
| Loft PIV Unit (standard) | Houses and bungalows with loft access | From £825 | 7 years |
| Loft PIV Unit (heated) | Properties where a heated unit is preferred | From £950 | 7 years |
Prices correct as of 2026. Actual price depends on property size, loft configuration and access. All quotes are provided free of charge following a site assessment.
A PIV system is not a universal solution for all damp problems. Here is a straightforward guide to when it is and is not appropriate.
In these cases we will identify the actual cause and recommend the correct solution, which may be a damp proof course injection, repointing or structural repair.
We cover all of Greater Manchester and beyond. Our core service area for PIV installation includes Manchester city, Tameside, Stockport, Trafford, Lancashire, Oldham, Rochdale, Wigan, Bolton and Bury. For large-scale landlord or housing association contracts, we travel nationally. Call to discuss availability in your area.
Call for a free assessment and fixed price quote. We cover Manchester, Tameside, Stockport, Trafford, Lancashire, Oldham, Rochdale, Wigan, Bolton, Bury and surrounding areas.
07791 561944Mon-Fri 8am-6pm, Sat 9am-4pm
