The Ranch Renovation EnerPHit Step 1

  • EnerPHit   •   July 9, 2019

Recap of the first step of our step-by-step Passive House renovation project.

Comfort, or rather lack thereof in large parts of the house during wintertime, was the main driver to start with the first renovation measures. Here is a list with more details about the original comfort situation:

Cool and comfortable house in summertime

Cooling is hardly needed anytime, only in the addition, when it is very hot and the sun hits the sliding door glazing in the afternoon. We would manually ventilate the house in the early morning and at night by opening windows and patio doors.

Cold and very uncomfortable house in wintertime

Back of the house is especially cold during winter. This area includes bed- and bathrooms as well as 2 offices;

Bath towels don’t dry in winter;

Warm front house with running heater with cold spots along walls and leaky doors;

Walls and floors very cold in winter;

House does not warm up, even on sunny and warmer winter days it feels like a fridge.

No air flow in master bedroom

Room always felt uncomfortable but CO2 values are ok.

Had to sleep with open windows even during cold winter nights.

Here is a quick rundown of the relevant building assemblies and systems before I go into more detail about the measures of this first Passive House renovation step.

Building Assemblies  – before –

During Blowerdoor testing I could not even pressurize house to 50 PA. House has a vented gas dryer, 2 fireplaces (one without damper), many cracks and openings around  incoming pipes. Based on the measured 5641 cfm (cubic feet per minute airmovement) at 43.8PA, I calculated 18 ACH (air change per hour)! Passive House requirement for retrofits is 1.0 ACH. We have a VERY long way to go but also many opportunities to get there over time.

Wall was original 1948 construction with 8″ hollow concrete blocks with rebar inside and a few layers of paint on the in- and outside. Insulation value: NONE

With the exception of the addition, which was build with 91/2″ monolithic hempcrete walls. Insulation value: R21

In some areas insulation has never been replaced; in some areas it was replaced or added on but installed improperly (gaps between rigid insulation, missing pieces and different thicknesses). Again with the exception of the addition. A 9″ denim batt insulation was installed (properly) in the cathedral ceiling below the roof.

The concrete floor does not have any insulation at the outside edge or underneath. The slab also extends to the outside veranda, breezeway and other concrete extensions 3/4 around the whole house. Huge thermal bridges!

Besides the sliding doors in the addition all windows are equipped with deep enough overhang to avoid the sun reaching the glazing in summer. Half the house is enclosed with an 8′ veranda and the rest with 3′ overhangs. The sliding doors have 2′ overhangs and face south/west.

Each of the original bathtubs was installed on the outside wall with no wall insulation and no insulation beneath. They literally sit on the dirt. Huge thermal bridges!

Standard double glazed windows provide different grades of performance due to different levels of code requirements at time of installation. Windows are not airtight enough and U-Value is too high to be considered high performance.

The findoes and sliders in the south/west facing addition are only equipped with 2′ overhangs and only partially protected from the lower afternoon sun in the West.

If our architect for the additon would have had a  better understanding of building science and would have created a sun study in Revit or SketchUp, the solar heat gain in the addition could have easily been avoided.  Unfortunately back then I didn’t not know either. We could have avoided this issue by asking better questions before we hired our architect. 

Dutch doors are nicely restored but without insulation, gaps and single glazing in nupper part of the doors.

Systems  – before –

The minisplit system is located in the addition and it is the main heating and cooling source for the whole house. Before we build the addition our main heating source was our two fireplaces in the front of the house and the we did not have any air-conditioning. Years ago we closed down the radiant floor heating because it had one too many leaks and we got tired cutting open the concrete floor for repairs. We live in an area with clay soil and lots of movement.The radiant heating system with copper piping was part of the initial construction in 1948 and had to be repaired many times. The system was 65 years old when we retired it.

Used occasionally during winter nights to fight the cold coming in throught the iron-cast bathtub thermal bridges.

Used occasionally during winter time when working in the back offices at night.

Our 40l gas heater and the 2 bathrooms are on opposite end of the house. It takes a few minutes until hot water arrives in the bathrooms.

EnerPHit first steps