MODELLING, MONITORING & MEASUREMENT

 

Introduction

 

A Healthy Home is designed to be a high quality, resilient, warm, dry, healthy, energy efficient and sustainable living environment.

 

But how do we know that the design does what it says on the tin?

 

We need a feedback loop to check that the design is fit for purpose and to tweak it if it isn’t.

 

It is only through an evidence based; data driven approach that a home’s design can be endorsed and what a Healthy Home stands for, verified.

 

It is through modelling, monitoring, measuring and reporting that the design can be validated or tweaked to achieve the desired environmental quality, energy usage and sustainability targets.

 

Building Code Requirements

 

There is no requirement within the Code documents for modelling followed by ongoing monitoring and measurement.

 

Designing for Performance

 

Energy modelling is still not common in the New Zealand building industry but is increasing in importance as the awareness and urgency grows for climate change mitigation. Several software tools are available for energy / thermal modelling of buildings. Sketchup has an affordable add-on called designPH which interfaces the Sketchup 3d model with the Passive House software, phpp (passive house planning package). There are other programs, like Sefaira, Energy plus and some CAD programs integrate energy modelling, eg. ArchiCAD and Revit.

 

Modelling software should be used to validate design requirements but not control the design itself. Do not become a slave to the software!

 

Measuring Performance

 

Successful Measurement and Reporting

 

In this section we will define and provide instruction on how to measure the performance of a Healthy Home, to verify quality, provide real-time insight into performance of the home and empower future design decisions through a digital data driven validation model (DDM). Any solution that fits the performance measuring requirements will be accepted as long as it produces data that can be tracked and recorded against time over at least a year.

 

To successfully measure and report on the performance of a Healthy Home, the following is required.

 

● A completed design/model.

 

● Indoor Environmental Quality (IEQ) monitoring equipment which measures:

 

- Temperature.

 

- Relative Humidity.

 

- Carbon dioxide.

 

- Ambient Lighting (optional).

 

- Ambient Sound (optional).

 

- Outdoor temperature and relative humidity monitoring.

 

- Energy consumption monitoring.

 

- Total incoming electrical consumption.

 

● Total exported electricity (If available/optional).

 

● Water consumption (if available/optional).

 

● Gas consumption (if available/optional).

 

The Context of Measurement

 

Measuring is only useful when the measurement has context. Before any measurement is done the context around that measurement needs to be created such as:

 

● The physical address of the home.

 

● The number of floors.

 

● Each floor must be divided into “spaces”.

 

● Each space must be associated with a room type (bedroom, bathroom, kitchen, lounge, etc).

 

This will result in a basic floor plan against which monitoring equipment can be installed and context provided.

 

An example of why this is necessary can be explained by this statement:

 

“Very high temperature reading of 32°C at 3:30pm in west facing bedroom on the first floor with single glazed windows, aluminium frames and no fixed sources of ventilation, heating or cooling”

 

As opposed to reporting the temperature only, the modelling information has given you the context to draw a conclusion as to why the temperature in that room is so high.

 

Monitoring and measurement

 

Monitoring and measuring performance is crucial to validating every Healthy Home. In the same way that you would expect smoke and fire alarms to be installed within a home, a Healthy Home requires indoor environmental quality monitoring to be installed.

 

Monitoring and measurement is expected over a minimum of 1 year, which will ensure that performance is met during all seasons. A second year is encouraged to validate any changes be it structural or occupancy behaviour.

 

Monitoring Indoor Environmental quality (IEQ)

 

Monitoring IEQ is crucial to understanding and validating a Healthy Home’s performance. Ideally the IEQ monitoring equipment is required in:

 

● Every Bedroom.

 

● The larges common living area.

 

Optional IEQ monitors can also be installed in:

 

● Kitchens.

 

● Bathrooms.

 

● Other habitable spaces.

 

Along with IEQ monitors, a single temperature and relative humidity monitor should be installed outside the Healthy Home to provide a comparison with the day to day weather variations. Measuring IEQ in this way gives insight into how the indoor environment of the home is responding to occupant behaviour in relation to the external weather conditions.

 

Installing Monitoring devices

 

IEQ monitoring devices must be installed under the following best practices:

 

● Between 1.2m and 1.6m above the floor.

 

● On an internal wall.

 

● No direct contact with sunlight.

 

● Not under or above any fixed sources of heating or cooling.

 

External monitoring devices must be installed under the following best practices:

 

● Unless waterproof the device must be installed in a location that does not come into contact with rain or water. (ie: under a carport, flashing or under a roof overhang).

 

● No direct contact with sunlight.

 

Monitoring Energy Usage

 

Monitoring a Healthy Homes energy usage in conjunction with IEQ and external weather conditions is vital to understanding performance. A Healthy Home demonstrates comfortable living while remaining energy efficient and sustainable.

 

Comparing IEQ with energy usage monitoring ensures that a comfortable living environment doesn't come at the expense of higher power consumption and cost.

 

Ideally an energy consumption monitoring device should be installed on the main incoming feed of the home and on the hot water and heating supplies. All energy monitoring devices must be installed by a qualified electrician if the device requires access to the distribution board or the main power supply.

 

Alternatively, power bill data can be used but this will not provide specific data on heating costs.

 

Suppliers

 

Tether provide a range of devices for performance monitoring with easy to use software that records data over time.

 

For more information https://www.tether.co.nz/

 

Recommended Healthy Home guidelines for Modelling, Monitoring & Measurement are set out in the table below: