Horse Stable Ventilation

Figure 2. Design detail for freezing conditions, such as this self draining water hydrant, will be needed in most horse stables.

What about drafts?

A draft occurs when cold air blows on a horse. Warm air blowing over a horse is not a draft. Since horses tolerate colder conditions than humans, what we consider drafty is not necessarily uncomfortable to the horse. Be sure to differentiate between cold temperature and draft. A main principle of ventilation is that even very cold fresh air can be introduced into a horse stall, so when mixed and tempered with stable air, it no longer has the air speed and chill of a draft.

What about air distribution within the stable?

An open, unobstructed interior helps move air around the stable. Provide airflow between the openings in the stable where fresh air enters and stale air exits. Fresh air is brought into the horse stalls where it picks up moisture, heat, dust, and ammonia and can exit out another opening. Stuffy stables, and their poor air quality, are the product of limited air exchange and/or obstructions to getting the fresh air to where the horses are stalled.

An open, unobstructed interior gets fresh air to the horses and provides an exit path for stale air.

Go into the horse stall to determine the air quality of the stable. Moisture, odor, and ammonia are generated primarily in the stalls, where fresh air is needed for horse respiration and to dilute air contaminants. Since most dust and ammonia are down near the bedding and manure, check air quality near the floor as well as at horse-head height. Floor-level air quality is particularly important for foals or when horses eat at ground level and spend time laying in the stall. It is not uncommon for the stable's working aisle to be breezy and well ventilated while the stalls suffer from stuffy conditions.

How much ventilation should be provided?

Natural ventilation is often expressed in "air changes per hour." An air change per hour (ACH) means that the total volume of air in the stable is replaced in an hour's time. Six air changes per hour means a complete air change every 10 minutes. Provide 4 to 8 air changes per hour to reduce mold spore contamination, minimize condensation, and reduce moisture, odor, and ammonia accumulation. For comparison, the modern home has 1/2 air changes per hour from infiltration through various cracks, such as around doors and windows. This recommendation for stable ventilation is substantially more than the average residential air exchange rate to maintain fresh air conditions and good air quality in the more challenging stable environment.

How is ventilation provided to the structure?

Figure 3. Horse stable ventilation uses architecture with openings along sidewalls and ridge to accommodate the two forces behind natural ventilation: thermal buoyancy and wind.