How to heat a marquee or tent

In Weddings by Joni

Fall and winter weddings are perfectly possible outside in a marquee or other garden or farm structure.  The main difference is that you will probably need to supply heating.  Here are the answers to the most frequently asked questions about heating a marquee or tent.

For my video on this topic go to YouTube.

Which heaters are safe for a marquee?

There are several types of heater available for rental or purchase but not all will be right for your event.

Patio heaters are often used in the area immediately outside a building such as a bar or restaurant.  They certainly take the chill off the night air.  The clue to their safety is that word ‘outside’.  They are tall and must be kept well clear of the sides or roof of the tent.  They don’t mix with draped fabric ceilings or hung bunting.  

When the propane gas cyclinder is full they are reasonably stable but during your event as the gas is used the heater will become less stable.  So you need to make sure your patio heater has some type of container at the bottom for sand to keep it steady even when empty.   Wind gusts, little children running around and ‘helpful’ guests reorganising the heat can all cause the heater to topple over with grave consequences.

Best advice is not to use a patio heater inside a marquee but to place one or more in any outside area where people will be standing around such as a bar area or entrance to the marquee and to ensure it is heavily weighted by more than just the fuel.

If you see direct fired heaters, or industrial space heaters for rent you may be tempted by the cheap prices.  But they are only for large areas with good ventilation as they produce some toxic fumes.  Construction sites use these but they are definitely not for tents or marquees.

Indirect heaters sit outside the tent and have a long flexible tube that is pushed through the join in a wall of a tent.  An air flow mechanism is fitted to the inside end of the tube and a thermostat.  They are heated by oil or propane.  The fumes are taken up a chimney and released into the air above head height.  As they are warm, they rise immediately and cause no problems to anyone nearby. Only hot air enters the tent, no fumes at all. These are what most event companies use. 

Infrared heaters sit high up in the marquee affixed to a stable part of the structure, often in the top corners of each wall.  They need to be well away from where anyone can touch them.

For a small tent electric fan heaters sit at ground level and are safe.  Position them out of the way of where small children could play with them or trip over them.

Which heaters are quiet?

Any heater with a fan will make some sound but your guests will make a lot more!  Sound is not a primary concern for wedding receptions as so many people are chatting.  However the indirect heaters outside the marquee make no sound inside at all.

Which heaters look best?

Whilst patio heaters are now a well-known design which immediately invokes memories of convivial outdoor evening meals they do take up space.  The wall mounted infrared heaters look good and seeing them will remind you to turn them off when not needed.  The external indirect heaters take up no precious space inside your event structure and are invisible to guests as they sit out of the public areas, at the rear of the marquee.  They either have a built-in fuel tank or gas cylinder or these are separate on larger models.

Which heaters don’t smell?

Propane gas is especially manufactured to smell unpleasant.  That is to alert you if gas is escaping.  But normally there is very little smell when they are well maintained and burning well.  But it’s another reason to site a propane heater outside rather than use a patio heater inside the tent.

What are the cheapest heaters?

Patio heaters are inexpensive but probably not the best choice for safety and space reasons. 

Floor level electric fan assisted heaters are inexpensive but you may need several depending on the size of your marquee.  In general they are not recommended for tents larger than 600 cubic metres (see below for how to calculate this).

Direct gas or oil heaters are cheap but unsafe when used inside a closed area or near people or flammable décor.

Indirect heaters are quite expensive but are the obvious choice for a larger tent or structure.

How to calculate the size of heaters to use?

First calculate the size of the space to be heated.  Then decide on how much power you need.  Then decide whether you need just one unit or more.  One very large unit may not fit through the access you have such as a narrow gate or along a narrow path.  But most indirect heaters for events are on wheels and are built to pass through a single gate or doorway.

You need to measure your marquee in cubic metres or cubic feet (USA).  That means multiplying one long side by one short side by the height.  Reckon that 1 KW heats around 10 cubic metres or 350 cubic feet.  So for example a 9×16 metre marquee or smaller will need one indirect heater of 25KW whereas a 9×18 tent will need two.

Is it better to rent or buy heaters for an event?

Unless you expect to use the heater frequently it is far better to hire it for your big day.  It will seem expensive for a single day but it comes with benefits so remember to ask your rental company to include these:

  • Pre-event survey of the site
  • Exact calculation of the best heater position and number or size of heaters to use
  • Complete delivery and set-up of the heating system (be sure to know where the best electric source is)
  • Supply of the heater, the fuel source and the connections
  • Flexible ducting and air flow dispenser if using an indirect heater
  • Fixing for top-of-sidewall mounting if using infrared heaters
  • An all-weather connection to the electricity supply
  • A heavy duty extension cable to run from the nearest supply point (eg your house), with event industry standard fixings to hold the cable in place or cover it where there is any danger of guests walking
  • Extra fuel if needed
  • Support and advice plus an emergency call-out number in cases of problems or safety worries.

Most marquee or tent hire companies will already have their preferred methods of heating and their preferred suppliers.  But, even so, you should read through the notes above as it’s difficult to decide between companies unless you have some idea of the pros and cons of the solutions they suggest.

If you’ve used any of the types of heating I mention please give your rating for how satisfactory it was in the comments area below. Other readers would welcome your input.