While every home is different, after countless load calculations and measurements, we’ve found common patterns for homes in the Snoqualmie area.  Below are the most common questions and scenarios we encounter.

Snoqualmie Ridge specific questions and answers

You need a new furnace, but you’re not 100% sure you want to add AC at the moment

This is a bit tricky, and frankly, it will sound like upselling.  While unnecessary upsells are very common in the HVAC world, this one is legitimate.  Adding air conditioning requires installing a coil (roughly 20″x20″ box) directly above or below your furnace.  If this is done while replacing the furnace, it is a fairly easy process.  Everything is removed and you have a clean state to start from.

Most furnaces on the Snoqualmie Ridge are downflow units (see image below).  This means the new AC coil sits beneath the furnace.  If you wait to add AC, we’ll need to remove the entire furnace, set it aside, install the coil, and finally, reinstall the furnace.  This requires the same amount of time as installing it in the first place, so you’re essentially paying for the labor twice.

You would like to add air conditioning, but your furnace is still working

Many furnaces in the Snoqualmie Ridge are nearing the end of their expected service account.  If a furnace is ~15+ years old, and you’d like to add a heat pump or air conditioner, it’s a straightforward decision.  It’s much less costly to replace everything at once.  If we retain the old furnace, we’re severely limited on which heat pumps we can install.  Modern, high efficiency units communicate with the furnace.  If the old furnace is kept in place, we can only install the most basic heat pump/AC compressors.

You recently replaced your furnace, but didn’t install air conditioning

A couple of options are available.  If you want a mid/high end heat pump and you installed a mid/high end furnace, you’ll be best served by working with a contractor who is a rep for your brand  of furnace (i.e. Lennox, American Standard, etc.).  This will allow you to stay consistent between your furnace and your heat pump/AC.  Mixing and matching brands is not ideal and should be avoided if possible.

If you recently installed a basic furnace, the brand of heat pump/AC you choose to install is less important.  You’re constrained to a lower end unit in either scenario.

The temperature differences between your floors is high

Homes on the ridge are mostly 2 story constructions.  A common complaint is the temperature difference between the floors.  In many cases, a 5-7 degree temp difference can occur during warm weather.  This is due to two key factors, the stack effect and ducting constrictions.  The first occurs in every home and is simply due to the fact warm air rises.  This can be somewhat mitigated by moving air around, but without zoning, it cannot be completely eliminated.

The second factor, constrictions in the ducts, is due to the original construction of the house.  Most homes built in the 90’s and early 2000’s were not designed with rigorous load calculations.  In many cases, the size of the equipment (furnace and/or AC unit) isn’t the issue, it’s the ducting installation.  In the summer, the upstairs needs the most airflow.  Yet, due to the design decisions of the architect, there isn’t space to install a sufficiently large duct to service this area.  Making matters worse, the ducts often have many twists and turns on their way to the upper floor, further restricting the flow.

Can’t I just increase the size of my air conditioner?

In most cases, no.  If the ducts are already restricting the airflow, increasing the size of the outdoor unit will not help.  In fact, it will almost assuredly decrease the performance of your system.  First, the unit will short cycle, causing the system to turn on and off in short periods of time.  Not only does this increase the wear and tear on the system, it reduces the ability of the air conditioner to remove moisture.   And ideal system runs nearly full time.  Oversizing the equipment will reverse this optimization.

Increasing the size of the air conditioner can also lead to condensation. If the power of the air conditioner increases, but the ducts remain the same, the air coming out of the system will drop, but the velocity will remain the same.  This causes very cold temperatures to occur on the registers and any other exposed metal parts of the system.

The bad news – fixing this directly is quite difficult and involves major sheetrock removal.

The good news – temperature differences between floors can be achieved with a separate mini-split.  The most cost effective option is to pick your highest priority room and install a single head mini-split.  This will provide individual temp control for the room, completely independent from the rest of the house.  Our favorite solution is a one-way cassette.  These are mini-splits installed flush with the ceiling.

Potential HVAC rebates for the Snoqualmie area

The majority of the Snoqualmie area, including Snoqualmie Ridge, fall within PSE’s combined gas and electric utility zone.  If you live in the areas north and east of town that fall within unincorporated King County, you’re likely on PSE electric, but not gas, or Tanner Electric.

PSE customers in Snoqualmie:

• $1,500 rebate when converting from electric resistance (i.e. baseboard heaters) to heat pumps. Note, this applies to both ducted and ductless installations.
• Low income households may qualify for a $2,400 rebate boost.
• Systems must by AHRI certified and meet minimum efficiency requirements.
• If installing a ductless/mini-split system, at least one of the indoor head units must be installed in the main living area of the home.  A single mini-split installed in a bedroom would not qualify.

Climate conditions

The climate conditions in the Snoqualmie Valley are slightly more extreme than the Seattle / Bellevue area.  This is less due to the proximity to the mountains or elevation, but rather due to the distance from the mitigating effect of the Puget Sound.

Snoqualmie does not have state mandated outdoor design conditions.  Design conditions are the temperatures HVAC contractors and engineers use to size a building.  In most areas, this is the 99th percentile.  The city of North Bend dictates winter design temp of 27F.   Due to it’s elevation, Snoqualmie Ridge tends to run slightly cooler in the winter.

Clearly, there are occasions when the temp falls below 27F.  However, HVAC equipment, especially heat pumps, are not designed for the absolute coldest days of the year.  If they were, they would perform poorly the other 99% of the time.

On Snoqualmie Ridge, the design factor isn’t hugely important, as nearly all homes with a heat pump also have a gas furnace.   In these arrangements, the heat pump is sized for air conditioning loads, and the furnace takes over during extremely cold weather (typically below 30F).