HVAC Design

A house insulated with foam is highly energy efficient.  This should be taken into account when designing the Heating, Ventilation, and Air Conditioning system (HVAC).  It is not only possible but necessary to reduce the size of your A/C unit to ensure proper operation and moisture removal in the summer.  By reducing the size of your furnace and your A/C unit, you will reduce both the installation and operating costs. 

An air conditioner is designed to remove heat (called “sensible” load) and moisture ("latent" load) in a fixed ratio. Taken together, the sensible and latent cooling loads make up the total capacity needed in your system.  Because your home is well insulated, the latent load will make up a higher proportion of the total load than is the case in more common, less energy efficient homes.  Rather than focus on the total load, it is advisable to size the system to match the latent load even if this may result in a slight undersizing with respect to sensible load.  An excellent article on HVAC design is available on Toolbase Services’ website.

We also recommended that you install a ventilation system to provide fresh air in an energy efficient and controllable manner.  An Energy Recovery Ventilator will run on very little power, recover up to 95 percent of the energy contained in the exhaust air, and provide moisture conditioning as well as ventilation.

Your furnace and water heater should be high efficiency, sealed combustion designs.  By using such units, you will reduce your energy consumption.  If you choose to install less efficient, open combustion units, you must provide a supply of combustion air to avoid the risk of back-drafting which can be potentially dangerous.