Tips on Installing a New Forced Air System (HVAC) in my Home

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“I have a 30 year old furnace in my home, and it’s never quite comfortable everywhere in the house in the winter. How will getting a new forced air system installed help me?”

Our civilization never really got the whole forced-air heating thing figured out for homes until fairly recently. Previously, systems were loud, uncomfortable (too hot or cold), ill-configured, poorly placed, energy-inefficient, and injected asbestos fibers into our breathing air.

But in 2012, we pretty much have it sewn-up. Here’s what you need to know if you are contemplating a new forced air system:

First, let’s break the whole forced air system down into it’s components:
The Furnace itself, that heats the air and pumps that heated air out into the system through…
The Ducting, that carries the heated air from the furnace to the supply registers (the grilles) in each room throughout the house. This air then returns to the furnace through…
The Cold Air Return, which recycles the air back through the big grille in your hallway (usually), to the furnace for re-heating (or cooling), passing it through…
The Filter, which removes dust and other particulates from the air.
Controlling it all is the Thermostat, which tells the Furnace when to turn on or off

There are optional system components as well, being:
A filter equipment upgrade, for even better filtering of our breathing air,
Outside air systems, which bring in fresh air from the outside to ensure oxygen-rich, healthy air on the inside,
Zoning equipment, so that you don’t need to heat the entire upstairs if you’re not using it,
Air conditioning equipment, for obvious reasons, and
Remotely programmable Thermostats, controllable from the internet.

These additional upgrades are nice (and of course cost more), and you may or may not consider them worthwhile.

The Furnace itself has a few options:
Efficiency ratings. While some municipalities still allow ratings as low as 80%, the 95% units are becoming more the norm. One advantage of these higher-rated systems is that they no longer need a flue carrying toxic gasses to the roof, using instead PVC pipes that can exit the building at exterior walls. This means that the number of options for placement of the unit just increased substantially. Combine that with the horizontal units available instead of the traditional vertical ones, and you can easily reclaim your closet or make better use of that garage space.

Dual Stage and Variable Speed Fans. In my opinion, this is by far the most beneficial upgrade (unless you need AC). With this option, you can run the furnace fan without firing up the heater at very low speeds 24/7 and not even know it’s on, it’s so quiet. Combined with a filter upgrade, it’s a must for anyone with respiratory issues, multiple pets, or if you just want dust-free air.

And when you are using the heater, the unit will blow the air through the system at low speeds when able, high speeds when needed. No more of the too-hot/too-cold cycles of the past.

It turns out that Duct Tape was not such a good idea after all… A quick word about Ducting:
Increasingly, municipalities are requiring pressure-tests of the ducting as part of the permitting process. This means sealing failed ducting joints that are leaking hot air and $ into your attic or crawlspace under the house. Quite often the entire duct (or just the joints) were sealed with asbestos in it’s most problematic form. Also quite often, the ducting was not sized or placed correctly and the system requires re-configuration to work as efficiently and comfortably as possible.

Your unique solution will depend mostly on your budget and the requirements of your local Building Department during a remodeling project. A quick visual inspection by a professional should tell you exactly what you need to know.

Very Important! The modification or replacement of a forced air system is, unfortunately, something that often gets overlooked during the project design and budgeting process. Don’t let this this happen to you! Ask your design professional about it, and make sure to include an exploration of requirements and possibilities in the early stages your design development process. Don’t leave it off for last- Change Orders are the last thing you want.

One more thing: It’s important to understand that your average HVAC installer assumes you are talking to other installers and is therefore incentivized to give you pricing on the best short-term solution. Your best advice will come from an experienced Builder with an eye for the “big design picture” and the long-term investment strategy for your property in order to keep costs minimized for potential projects down the road.

Got a question about your home? Here’s your chance to ask the “Design-Build Advisor!” Give us a call at 415-459-3349 or send your question to john@theperfectbuilder and we’ll answer either in this blog or by e-mail.

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