National Heating & Cooling guarantees that when the equipment we have installed is maintained and operated in accordance with the manufacturer’s operating and maintenance manuals, the system will perform as we have stated and agreed upon. We have promised a maintained temperature variance of no more than 3 degrees from your temperature selection to the actual temperature at your thermostat when you are heating or cooling your home under normal operating conditions. If the installation temperatures are not achieved, we will make any necessary modifications, repairs or replacements at no charge to you for a period of 5 years. This guarantee is meant to guarantee that the equipment we install is sized accurately for the home at the time of installation. It does not cover situations where the home does not maintain proper temperature caused by a component or part failure.