FAQ'S

Recotherm have been building ventilation systems for indoor pools for 26 years and have refined there system so to reduce the running cost to as little as possible.

A simple off the shelf ventilation unit would not be able to offer the energy saving features of the Recotherm unit and would not be able to with stand the corrosive effects of the swimming pool atmosphere. Recotherm have units in operation that have been running for 25 years.

No this is a myth. Condensation occurs when air is in contact with a surface that is colder than the dew point of the air. The dew point of the air is a function of the temperature and humidity of the air. You can have the air temperature 5 °C below the pool temperature as long as the dew point of the air is below the temperature of the internal surfaces.

The Recotherm unit controls the internal humidity and temperature and thus controls the dew point. With an external temperature of -1 °C and a room temperature of 30 °C a humidity of 50% will prevent condensation on a double glazed panel.

If the air temperature was 25°C then a humidity of 55% would prevent condensation on a double glazed panel.

Recotherms expertise lies in swimming pools, so any comments we make are specifically related to swimming pools. There is no specific information from the Government with regards to pools, but we can apply the government guidance which has been produced, in conjunction with the CIBSE (Chartered Institute of Building Services Engineers) the current advice is:-

“It is recommended that any ventilation or air conditioning system that normally runs with a recirculation mode should now be set up to run on full outside air where this is possible. 

In buildings with mechanical ventilation systems extended operation times are recommended. In demand control systems CO2 set points should be set to 400ppm to increase the delivery of outside air. Ventilation should be kept on for longer, with lower ventilation rates when people are absent. It is not recommended to switch ventilation systems off in any buildings, even those temporarily vacated, but to operate them continuously at reduced speeds.

Recirculation of air between spaces, rooms or zones occupied by different people should be avoided. However, in the case of any systems serving a single space, partial recirculation of air within that space, such as through a local fan coil unit, is less of a concern. The reason is that the primary objective is to maximise the air exchange rate with outside air and to minimize the risk of any pockets of stagnant air.”

Normally in a swimming pool we are serving a single area so some recirculation is accepted. There are a lot of systems on the market that use mechanical dehumidifiers and only introduce a small amount of fresh air indeed there are some that don’t introduce fresh air, at all. These systems will find it difficult to comply with the latest government recommendations without fundamentally redesigning their units. That is because the fresh air they have to introduce, because of COVID, will eliminate the need for a dehumidifier.  Most of the units on the market that use mechanical dehumidification do not have any other form of heat recovery on the fresh air, so they become total lost and you end up heating the local county.  

At Recotherm we have always championed the use of fresh air as the best way to dehumidify the pool hall, so every unit we sell can bring in large amounts of fresh air.  Indeed, wherever possible, we have designed our units to be able to run on full fresh air, even in the middle of the winter when the ambient temperature is at its lowest.

But there is a downside to switching to full fresh air, in the Winter the ambient air contains very little moisture so only a small amount, say 10-20%, is required to control the humidity.  Under these circumstance the Recotherm units would normally reduce the amount of fresh air introduced, but if we are to stipulate that they must operate a higher fresh air rates, then the internal humidity will drop increasing the evaporation of the pool and thus increasing running costs – but also it will make the wet occupants feel colder as the water on their bodies evaporates quicker. 

So, I feel we need to be flexible.  We need to increase the level of fresh air, but not to a point where we are deterring people from coming to the pool because they feel cold.  It may well be that in 5 years’ time, when we have had time to analyse the data, that we find out that COVID cannot live in a swimming pool environment. But for the moment we have to err on the side of caution and increase the amount of fresh air to a level that is sustainable without affecting the daily running of the pool. 

Yes a spa pool is at a high temperature than the pool and when in use is highly active you should let who ever is selecting the unit know that you have a spa and what size it is.

No a heat pump dehumidifier is just a different type of unit it works by recirculating the air and removing moisture in a direct expansion evaporator the heat from this process is then use to heat the air and water.

Unfortunately the dehumidification process runs on electricity which is expensive and by recirculating the air without removing the chlorine and body odour smells it give a poor atmosphere in the pool hall. The Recotherm unit will give you a better atmosphere and cost less to operate.