Sep 10, 2011

HVAC is back!

The HVAC system that was in our house many moons ago was a piece of junk! We tossed it almost immediately. During the bitter cold winter months we stayed warm by using a 55 gallon drum converted into a wood stove. Much of the house's old material was burned for heat and it saved us many trips to the dump. We also got to pretend we were hobos!  As winter turned to spring and eventually summer we really had no choice but to grin and bear it. Now the HVAC is back and better than ever!

There are some things we are just not qualified to do... and installing a heating and air conditioning system is one of those things. So, we hired this out to Ray and (with his as always) Garth from the John G. Webster Company. Yes that was a Wayne's World reference! After Garth designed the ducting system to ensure the proper flow of air to each room, the actual equipment started showing up. Here you can see the high eficiency gas furnace (left) and the AC coil (right) before it was installed.

As you all probably know by now, one of our goals has been to make this house as energy efficient as possible. One of the things we have done is insulate the house with expanding spray foam – no more of that pink fiberglass insulation for us! A side effect of spray foaming a house is that the foam completely air seals the house. A “normal” house breathes (read: leaks air) which allows for something called “air exchange rate”. Quite simply, this is a number that quantifies how many times per hour all the air in your house leaks out and is replaced by fresh air from outside. Sounds bad (and it is from an energy efficiency standpoint) however this is what allows you NOT to be breathing stale air all the time. So…long story short….the piece of equipment pictured below is called an ERV (Energy Recovery Ventilator) and runs in conjunction with the HVAC system to pull in air from outside and exhaust stale air from inside, since a spray foamed house like ours will not do this automatically through leakage.

Here is a diagram to show you how an ERV works:

The furnace and air handler were installed horizontally under the eve on the second floor to keep them out of our way. The house isn’t huge so this saved us a bunch of floor space. Here you can see the pan that goes under the furnace/air handler assembly that will catch any water, should it ever leak. After it was installed the guys attached a emergency shut off sensor that detects water in the pan and shuts the whole system down so the pan can't overflow and damage your house.

In an HVAC system you need to have both high and low air returns to cycle air that needs to be either re-heated or re-cooled, depending on the season, back to the furnace/air handler. Below is the smaller downstairs return that will pull cold air that has sunk to the floor back up for reconditioning.

 This picture is the high air return which is located at the top of the stairs. This will catch all the warm air that has risen to the ceiling and send it back to the AC system to be re-cooled.

Here you can see one of the registers in the upstairs bedroom before they connected the supply ductwork to it.

Here is the connected ductwork to one of the bedroom registers.

This is the main trunk that distributes air to most of the registers on the back of the house.

Here is the register in the kitchen.

Here is the furnace and the air handler all installed. Furnace is on the left and the air handler (which contains the AC coil that cools the air as it blows across) is on the right.


Here is the ERV all hooked up with its supply and exhaust ductwork. This will keep us supplied with fresh air without losing efficiency.


Our AC condensing unit sits right on the end of the house. You can see the refrigerant lines running up the side of the house, feeding right to the coil inside the air handler and cooling our house! We still have to move the electrical fuse box (the grey box mounted to the wall). Apparently, according to the “Code God” it is not “accessible” where it is but if we move it six inches to the left then everything will be fine. These people never fail to amaze us with their blatant disrespect for logic and insistence on “the book” which apparently was written by accident prone midgets who are incapable of reaching this box.

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