Garden Dome Ventilation: The Complete Guide

What ventilation does for a dome

A dome is an enclosed, glazed space, so airflow has three jobs:

• Manages heat. In summer, letting hot air out (it rises, so it escapes through the roof vents) keeps the dome from overheating.
• Controls moisture. In winter, fresh air movement stops humidity building up and helps prevent condensation on the panels.
• Keeps air fresh. Year-round, a little airflow keeps the space feeling clean and pleasant rather than stuffy.

Manage these three and the dome is comfortable whatever the weather, which is exactly what the included ventilation lets you do.

The ventilation you get as standard

You're not retrofitting anything. Every dome comes with:

• Roof vents. Built in to let warm, rising air and moisture escape, these are your primary, always-available airflow.
• A solid sliding door. Open it for a generous flow of fresh air and an easy through-draught.
• Windows. Open them to create cross-ventilation, pulling cooler air in on one side and pushing warm air out on the other.

Together these give you everything from a gentle background trickle of fresh air to a full flush-through on a hot day.

How to use it through the year

Summer: open the roof vents, and the door and windows on opposite sides, to create a through-draught. Vent in the cool of morning and evening to keep temperatures down. (There's more in our guide to keeping a garden dome cool.)

Winter: keep the vents mostly closed while heating to retain warmth, but open them periodically. A short burst of airflow clears moist air and helps prevent condensation without losing much heat, and a little ventilation even on cold days helps keep the panels clear.

All year: a small amount of constant airflow keeps the air fresh and the dome pleasant to be in.

Getting the balance right

The art of dome ventilation is balancing airflow against warmth:

• Too little airflow in winter and you risk condensation and stuffiness.
• Too much while heating wastes warmth.
• The sweet spot is vents mostly closed while you're heating electrically, opened periodically to clear moisture, and wide open in summer to keep cool.
• The exception is fuel. With any fuel-burning appliance, ventilation is a safety requirement rather than a comfort setting, so never shut off the air it needs.

It quickly becomes second nature, just like managing a conservatory or any glazed room.

Extra tips

• Heat dry. Use electric or infrared heat, never unflued gas or paraffin heaters, which add moisture and combustion gases to the air and defeat your ventilation (see our guides to condensation and heating a garden dome). Keep any heater well away from the panels.
• Fit a carbon monoxide alarm wherever anything burns fuel. A wood burner is a job for a HETAS-registered installer, with a proper flue and the clearances and air supply they specify (our wood burner guide has the detail).
• Don't add unnecessary humidity. Avoid drying washing inside.
• Position for the prevailing breeze. If you're siting from scratch, a spot that catches a gentle breeze helps natural ventilation.
• A fan helps on still, hot days to keep air moving.

Frequently asked questions