There is a trend towards electrification. In some large-scale operations it is challenging to provide electric infrastructure for high-consuming appliances. Heat-generating appliances such as furnaces, boilers, and patio heaters require a lot of British Thermal Units (BTUs). Other high-consuming electrical appliances such as vehicle chargers, refrigeration, air conditioning, elevators, and escalators further escalate the overall electrical demand.

In the case of patio heaters, a lot of power is needed to spot heat in outdoor areas, but only for short periods of time. Radiant heat warms the surfaces of the areas, tables, patios, and people, directly while the areas are in use. In some cases this can be more efficient than heating all the air in an indoor area, 24-7 during heating season. The high demand required by patio heaters is similar to using an instant hot water heater as compared to using a traditional hot water heater. The instant heater requires much more power for short periods yet is more efficient over time.

Outdoor seating areas are popular with customers and contribute to a healthy revenue stream through any restaurant, hotel, or club.

Alfresco Heating has worked with thousands of hospitality-industry customers. We calculate how many patio heaters these businesses will need and recommend the best option of patio heaters that run on gas, electricity, or a combination thereof, based on infrastructure.

Recently I provided a consultation for a brewery being built, which has expansive outdoor spaces, where heat is needed to ensure a good customer experience (and a good revenue stream). I suggested they would need in the ballpark of 50 x 50,000 BTU patio heaters. I compared that to 6000 watt electric patio heaters. They would need approximately 75 of those for equivalent heat. With gas patio heaters, the demand equals 2,500,000 BTU (input). With electric patio heaters, the demand equals 450,000 watts = roughly 1,500,000 BTU (input). 450,000 watts is a 1,875 amp load at 240 volts. (Load calculations are at the end of this article.) The gas demand can surely be met. It would be unusual for such a high electrical load to be feasible.

Some large areas may be heated with available electricity. For example, if 10 x 6000 watt patio heaters are needed to heat an area that’s 50’ x 20’, the 60,000 watts load would be a 250 amp draw, based on a 240 volt electrical supply. While an existing business would likely need an electrical service upgrade to power such a patio, it is likely that in new construction that sort of capacity could be built in.

Uncovered, wide open areas can only be heated effectively with upright gas patio heaters. It’s impractical and ineffective to heat open areas with portable electric patio heaters, which have very limited range.

Natural gas burning creates 39.8% of the electrical power we use in the USA according to the EPA. Whether burned locally or at central power plants, natural gas emissions are clean, producing primarily carbon dioxide, and not carbon monoxide, when well-engineered gas burners are properly tuned and maintained.

Please take a look at an earlier Alfresco Heating article about patio heaters and the environment. Key facts from that article:

• Electric patio heaters. The USA average of CO₂ generated per MWH (=1,000 KWH) of electricity is 818.3 lbs. Therefore one 6,000 watt electric heater creates an average of slightly less than five lbs. of CO₂ per hour, plus line losses.
• Natural gas patio heaters. Natural gas releases 0.0053 metric tons = 11.69 lbs. of CO₂/therm. A therm contains roughly 100,000 BTUs. A 50,000 BTU post heater CO₂ output is slightly less than six lbs./hour. One typical overhead gas patio heater uses 34,000 BTU per hour. CO₂ output is therefore slightly less than four lbs. per hour.

While things may change in the future, the EPA data shows that currently heating with electricity does not produce a significant reduction in environmental impact as compared to heating with natural gas. The infrastructure for delivering electricity is likely a limitation for large projects. In order to ensure a successful business with a strong revenue stream, Alfresco Heating suggests utilizing both natural gas and electricity for heating large outdoor areas. The following overhead electric and gas patio heaters are examples of models that we use to heat large areas.

• Infratech electric patio heaters are roughly 90% efficient at converting their electrical load into radiant heat. (e.g. Infratech CD6024 heaters have a 6,000 watt input which equals 20,473 BTUs input x 90% = an estimated 18,426 effective BTUs.)
• Unshielded high intensity gas patio heaters such as SunPak or Schwank are roughly 55% effective at converting their input BTUs into radiant heat. (e.g. SunPak S34 heaters have 34,000 BTU inputs x 55% = an estimated 18,700 effective BTUs.) When heaters need to be mounted higher then the BTUs need to be increased. (e.g. Schwank 2352 heaters have 50,000 BTU inputs x 55% = an estimated 27,500 effective BTUs.) These rough calculations are for radiant heat value and do not consider added heat retention value in covered and protected areas.
• Tube-type overhead gas patio heaters, such as those manufactured by Calcana and the Phantom by Schwank, can also heat efficiently and effectively when installed in suitable locations.
• Glass-faced gas patio heaters by SunStar can also heat efficiently and effectively when installed in suitable locations.

To learn more about how to choose patio heaters to warm your large outdoor seating area, give the outdoor heating experts at Alfresco Heating a call at 888-927-6456 or email them at glow@alfrescoheating.com.

© 2025 Alfresco Heating. All rights reserved. May not be copied or used without express permission