Hayward has developed an induced draft heater for above ground pools and spas that combines state-of-the-art technology with ease of operation and superior performance. Hayward's H100 is the perfect above ground and spa heater. The direct spark ignition and induced draft system make this heater impervious to high wind conditions. The H100 is easy to install and works on new and existing pools or spas. Choose between propane or natural gas.