# Leisure centre EPC upgrades: pools and ventilation > Why ventilation and dehumidification dominate a wet leisure building, how humidity and chlorine limit fitting choice, and where a dry gym differs completely. Source: https://commercialepcupgrades.co.uk/buildings/gym-and-leisure --- # Leisure centre EPC upgrades: pools and ventilation A wet leisure building is really two buildings. The dry side behaves like any other commercial space. The pool hall does not: it has to be ventilated and dehumidified continuously, not for comfort but to stop warm chlorinated moisture destroying the structure around it. That load dominates everything, and it never switches off. The operator, often a trust or a local authority contract, with the pool plant on its own replacement cycle. ## The pool hall runs to protect the building Warm, humid, chlorinated air attacks steel, finishes and fabric. The ventilation and dehumidification plant exists to prevent that, which means it runs when the pool is closed, overnight, and through the quiet season. You cannot schedule it away the way you can schedule lighting. That makes heat recovery, pool covers, water temperature set points and the age of the air handling plant the measures that actually matter. Lighting is a rounding error next to them, which is unusual on this site and worth saying plainly. ## What the environment does to fittings Chlorine and humidity are hostile to light fittings and to their fixings. Standard commercial fittings corrode, and a failed fitting over water is a very expensive thing to replace because of the access. - Corrosion-resistant housings and stainless or composite fixings, specified for a chlorinated atmosphere. - Appropriate ingress protection, and fittings rated for the zone they sit in above water. - Serviceability from a gantry or with the pool drained, because the access cost dominates the fitting cost. - Low glare and good colour rendering, because lifeguards must be able to see the pool floor. That last one is a safety requirement before it is an efficiency question, and it caps how far the specification can be value-engineered. ## A dry gym is a completely different building Take the pool away and the picture inverts. A dry gym is long-hours, high-occupancy, well-lit space with significant ventilation but none of the humidity problem. Lighting hours are long, which makes lighting payback fast, and the fittings face nothing worse than a sports hall ball strike. If you operate both, treat them as two projects with two business cases rather than one leisure programme. ## Opening hours are the other distinctive thing Leisure runs early and late, often five in the morning until ten at night, seven days. Long operating hours shorten the payback on anything that saves per hour of use, which is most lighting measures, and they also narrow the window for doing the work. ## Questions we get asked ### What is the biggest energy cost in a leisure centre? ### Can we use normal LED fittings over a pool? ### Is a gym without a pool the same project? Sources - A non-domestic EPC is an asset rating: it is based on the fabric of the building and its services rather than on metered consumption. [A guide to energy performance certificates for the construction, sale and let of non-dwellings, DCLG, 2014](https://www.gov.uk/government/publications/energy-performance-certificates-for-the-construction-sale-and-let-of-non-dwellings) Last updated 8 October 2026 . - [Plant and controls Where a wet centre actually spends](https://commercialepcupgrades.co.uk/measures/heating-hot-water) - [Lighting Long hours make the payback fast on the dry side](https://commercialepcupgrades.co.uk/measures/lighting) Next step ## Get a quote for your gyms and leisure centre One commercial contractor, quoting off a survey of the actual building rather than a rate per square foot over the phone. Or call [07367 293494](tel:+447367293494). Monday to Friday, 9am to 5.30pm.