I’m building a house with radiant heat floors (heat source is a gas-fired boiler), but want to add air conditioning and heat recovery ventilation. The house will be well insulated and tight. I want a system that will allow me to (1) bring in outside air in the winter with heat recovery, (2) air condition the house in the summer, and (3) bring in cool outside air in the summer (evenings) without air conditioning. I’ve checked a number of AC and HRV suppliers, and can’t find a unit that will allow me to do all three. Anyone have any experience with what I’m describing, or can point me in the right direction?
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Look for a Mechanical Engineer that will design the system for you. The equipment is available, and used in the commercial market. What you describing is an economiser, and involves a little smart technology. Although smart, they are still simple. It requires outside air temperature sensors, dampers with motor controls, and an HRV unit. A competant ME or HVAC design professional can spec. a system for you, based on your climate and load requirements.
I am currently looking for someone to do this type of design work for the house I hoo be starting this month. I'll post my findings when available.
Dave
Dennis,
This is something we do all the time in commercial buildings. No commercially availabe "unit" does this. We design systems that work as you describe using various components. However, because they (the owners/operators of commercial buildings) are constrained by code required minimum ventilation requirements, they seldom get to opt out of doing what you describe. Some things to consider:
- Unless you require the windows to be closed, the most realistic economizer for a single family home is open widows. Interior spaces of commercial buildings require cooling year-round and when the outside air temps are below 55, outside air is used to provide cooling. Seldom if ever will you require cooling in a residence when it is 55 or cooler outside.
- Use the HRV inplace of bath exhaust fans and connect the fresh air supply to the return of your air handling system. This way, you kill two birds with one stone. With a few DPST light swithes and relays, the system can be setup to operate when the blower runs (or continuously) or when any light in the bathrooms is turned on.