Part III: Importance of Maintenance and Upkeep for Maintaining Optimum Passive House Temperature Performance and Minimal Electricity Consumption

Maintaining Optimum Passive House Temperature Performance and Minimal Electricity Consumption

It's hard to believe, but it's been nearly seven years since we began construction and we continue to learn just how important it is to check and maintain various elements of our home in order to maintain energy efficiency and optimum temperature performance.

Mini-Split Maintenance

In a previous article, I covered the importance of frequently checking and cleaning the filters of the interior units of our mini-split systems.

This time around we address the evaporator and condenser coils.  Despite the use of the filtration, the interior evaporator coil (and fin assembly) did have a fair amount of buildup of collected particulate matter, the accumulation of which can significantly reduce their efficiency. Having a good number of pets including one Cockatoo certainly doesn't help.

The simple and inexpensive solution was to make a trip to Lowes and pick up a couple of cans of evaporator coil cleaner.  Armed with this, a brush, and paper towel we were able to clean the interior coils easily.

When the weather gets warmer, we will clean the outside condenser coils of both exterior units.

ERV Filter Maintenance

As simple and elegant as the Zehnder ERVs are, there are two elements of those systems that should be regularly checked and maintained.  The first ones are the enthalpy cores.  We generally clean them twice a year, once at the beginning of spring and once at the beginning of fall.  We detailed those steps in our previous article.

This time around, we worked on the intake and return filters.

The typical MERV 8 G4 filters that are standard with the Zehnder Novus 300 (Paul) are housed in a paper based frame.  The MERV 13 F7 filter, however, has a frame that is synthetic.  This allows for much easier cleaning and the potential for re-use.  The filters for the ComfoAir 200 both consist of plastic housings irrespective of the MERV ratings.

A trick that we learned is to put the filters in the dishwasher.  Prior to this, we submerged the filters in a warm water base consisting of a little bleach.  The outcomes were very good.

(Bottom filter: F7 MERV 13 for Novus 300, Top filters: red MERV 13 & black MERV 8 for ComfoAir 200)

We found the optimal filter combinations are to use the MERV 13 HEPA filters on the intake and the MERV 8 standard filters on the return.

Given that the humidity levels, during the warmer seasons, can be quite high at the intake side supplied by our earth air tubes, we also spray concrobium on the supply filters as well as lightly treat the enthalpy units and air flow interiors of the ERVs.  Unlike bleach, concrobium does an exceptional job at eliminating and reducing the potential for future mold growth.

Weather Stripping Examination & Maintenance

We found two "faults" in our weatherstripping that were the sources of two air leaks which were robbing our conditioned spaces of heat during this past winter.

The first one was an exterior Loewen swing door.  In this instance, one of our dogs had overtime been scratching at the outside door frame in an attempt to open the door using its handle (she is very adept at doing so).

Unfortunately, she ripped-up a good portion of the door frame's air seal and we didn't discover this for two winter seasons since the damage was primarily on the outside.  We only noticed the issue one winter evening, because there was a small ice build-up on an interior section of the door.

Fortunately, this was a very easy and inexpensive replacement part.

The second fault occurred at the threshold seal of our garage door.  While the garage is "semi" conditioned with a dedicated earth air-tube supply, interior garage temperatures during the winter can still get pretty chilly (typically, no lower than 35F-40F).

Was caused the damage was a threshold plate screw that had backed itself slightly and it eventually chewed up a portion of the weather stripping.

We only notice this because the laundry room and the hallway to the garage were feeling a little more chilly.  This seal, like the other one, was probably compromised for two seasons.

With a house that is as tight as ours (0.2 ACH50), these ostensibly little sealing failures can have a noticeable adverse impact air-tightness of the house as well as minimizing any room-to-room interior temperature variances.

In terms of general weather stripping maintenance, I would recommend checking the weather stripping of all doors and windows for any dirt, debris, or other potential failure.