Air Delivery Systems

Forced Air Delivery – Duct System

In this forced air delivery system you have an air handler with supply ducts coming out of one side and return ducts out of the other side.  The ducts are engineered using ACCA Manual D to assure correct airflow and static pressure.  The supply ducts branch off to the rooms in your home and terminate at the supply registers.  The registers, which we engineer to deliver the correct airflow based on the specific room’s needs, deliver the air so proper mixing occurs without directly contacting occupants.  Forced air systems, if done properly, can deliver some of the best comfort with great efficiency and remain almost silent when running.  With a properly designed system you should feel equal air temperature throughout the home without hearing or feeling it.  As an example, if done properly, a forced air heating system will be as comfortable as a good radiant floor system.

One reason that most forced air systems are not quiet, comfortable or efficient is because they are not designed or installed properly.  We specialize in duct installations and pride ourselves on delivering silent, comfortable and efficient duct systems.

A hydronic air handler forced air system numbers among the most efficient ways to set up a forced air distribution system. The difference between these and a furnace system is that a hydronic air handler brings in water from a high efficiency water heater and runs air over the coiled up hot water pipe heat exchange. Both furnace systems and hydronic air systems distribute air through ducts.


Mini Split System (ductless mini heat pumps)


A mini split system can be for heating, cooling or both.  It requires an outdoor A/C or Heat Pump compressor and a small indoor wall mounted unit.  Two refrigerant lines run from the outdoor unit to the indoor unit.  The indoor unit has cooling/heating coil and a fan which delivers the conditioned air to the room.  One outdoor unit can supply heating and/or cooling to one or multiple rooms.  It is great localized heating/cooling for homes without too many rooms, flats, office converted garages, workshops, etc.  They are very efficient and if you’re not using the rooms you can turn them off without losing efficiency.


Frequently Asked Questions (FAQS) on Air Delivery Systems

1) Do duct systems contribute to poor indoor air quality?

If incorrectly installed, they can do just this. Leakage either on a supply duct or on a return duct can contribute to poor indoor air quality. Return ducts especially due to the fact that when the system is on, return duct leaks pull in air from it’s surroundings whereas a supply duct leak would push out air. So a properly sealed and tested duct system with no leakage will not contribute to poor indoor air quality. A standard pleated filter, rated according to homeowner preference, will do provided it’s changed around once every 3 months.

2) What is a climate control zoned system? Are they efficient?

A climate control (zoned) system is one duct system divided into two (or more) sections and uses multiple thermostats in multiple different parts of a home. The concept is that when one thermostat is on and the other one is off, an electronic damper shuts off air to the part of the house with the thermostat that is off. This was invented to fix uneven temperature distribution issues in a home.

However, climate control systems are inefficient by definition. a correctly engineered duct system, as duct sizes do not fluctuate according to air flow, is only designed for one single constant air flow. So when one zone is off and another is on, then you have twice the amount of air trying to force it’s way through ducts that were only designed for half that amount. This results in high air flow resistance (static pressure), heat rise (furnace safety concern), noisy ducts/furnace/AC, and then high electrical costs as it forces the fan to work harder. In summary, it is far more efficient to have a duct system that cools/heats all parts of the house evenly than to shut off one part of the house when it’s not being used. This is assuming the duct system was properly designed. Zoned systems only give the illusion of control and energy savings.

3) Why are ducts always so leaky?

Home performance is a relatively new industry. The HVAC and construction industries often “factory line” projects to maximize profit. Corners are cut and short cuts are taken so that their prices can remain competitive. These same rules apply to most (in the past and still in the present) duct installations.

To make a long story short, if no Duct Mastic Sealant is used then the duct will most likely be very leaky. Mastic is a white paste that is applied thickly, twice over, to every single connection in the system. It is low VOC and relatively inexpensive. It should be applied to the inner membrane of a plastic flex duct and then slid onto the sheet metal duct connection. It can also be applied to the outside as a sealant and should be done in both ways. The state (california) average is 30% duct leakage. Eco Performance Builders is proud to average 0%-2% duct leakage for newly installed systems.

4) What is the Return on Investment (ROI) for new efficient ducts or a mini split?

Mini split heat pumps cost less per room the more rooms you split it too (within limitations of the system) and it does not take away from the efficiency of the system. This reduced cost per room is due to the fact that they are all tied into one outdoor unit which does not vary in cost depending on the number of rooms being heated/cooled. The return on investment is low if you have an existing: leaky duct system, oversized furnace/AC, old wall furnace/AC, or if you are using space heaters to currently heat a room.

New Ducts that are properly sealed, insulated, engineered and balanced have one of the lowest ROIs out of most energy upgrades if your existing system is leaky, poorly insulated or unbalanced. While you are waiting for your ROI, you have optimized comfort and much improved indoor air quality to enjoy.


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