ONE hole per penetration (Pipe, wiring) so it is easy to seal
Ventilation Research
Natural ventilation can generally provide a high ventilation rate more economically, due to the use of natural forces and large openings.
From a technology point of view, natural ventilation may be classified into simple natural ventilation systems and high-tech natural ventilation systems.
If properly designed, natural ventilation can be reliable, particularly when combined with a mechanical system using the hybrid (mixed-mode) ventilation principle, although some of these modern natural ventilation systems may be more expensive to construct and design than mechanical systems.
In general, the advantage of natural ventilation is its ability to provide a very high air-change rate at low cost, with a very simple system. Although the air-change rate can vary significantly, buildings with modern natural ventilation systems (that are designed and operated properly) can achieve very high air-change rates by natural forces, which can greatly exceed minimum ventilation requirements.
High ceilings and open plan layouts provide greater volumes of available air for the occupants and therefore, fewer ACH which reduces power consumption.
Australian NATHERS 7-star rating is 137 MJ/m2, 10 star is 1 MJ/m2
CO2 concentration <600ppm
Traditional Persian wind towers can provide cooling. They catch the wind and funnel it downward into the building. A vertical shaft will provide an escape for hot air (less dense) – a chimney effect. Drawing air over water will add humidity in a dry summer.
A taller stack provides greater buoyancy effects (Hot air rises – Taller stack exerts more pressure upward due to greater temperature differential at higher elevations). Also reduces effect of wind causing pressure drops and airflow reversals. Use an ‘H’ pot on top to prevent rain ingress and increase the exhaust effects (4 tube ends versus 1)
Use a radial fan rather than an axial fan.
Rate of flow is typically limited by inlets rather than outlets. Therefore, all outlets should be ‘Greater’ in flow capacity.
MHRV System and Air Filtration
Humidity levels should be around 50%, so the MHVR has to address that through ventilation and dehumidification. Airtightness target of <3 ach @50 Pa. Replace the air at 10l/s per person = 40cfm for 2 people.
Greenhouse has 80% humidity
The humidity for an indoor pool area should be set to between 50-60%RH
MHRV does not reduce humidity – an ERV does.
Belgian NBN D50-001 – Basic ventilation goes out through wet rooms and in through dry rooms.
Thicker the filter, the bigger the surface area and lower the resistance to airflow. DIY 4 filter system for 3ACH
Check filters every 3 months, change every year. F7 filters, except the kitchen extract (in the room extract point): Typically, a dust & grease filter of G3 grade is being used. Use grade 8 (One below HEPA) to decrease load on fan significantly whilst producing almost the same quality of filtration.
ISO 16890, where the classification of filters is based on the method of filtration determined by giving the particle size as the particulate matter it can filter and its efficiency as a percentage. (G4 class filters were the industry’s standards and complied with the now outdated EN 779 standard).
The Building Code requirement for fresh outdoor air ventilation requires ventilation for occupied spaces in accordance with NZS 4303:1990 Ventilation for acceptable indoor air quality. This sets the rate at 0.35 air changes per hour
Ecowindows supplied a German heat recovery ventilation system. 60% cheaper than Zehnder. Distributed MHRV with ceramic heat exchangers. Set to run only during times when area is used. No air filtering possible.
Filters commonly require replacing every 12 or 24 months.
- Includes Wireless Multi-Function Remote
- No Ductwork Required
- Thru the Wall installation
- Telescoping 6″ Vent Sleeve
- Wall Thickness 4 3/4″ – 11 13/16″
- Ceramic ERV Core SRE 91% @ 32F
- Aluminum Exterior Wall Vent Hood
- Anti-bacterial MERV 6 Air Filter
- Reversible Axial EC Fan
- Automatic Shutters
- 9 Ft Power Cord included
- 3 Speed Operation
- Efficacy 5.7 / 32 CFM
Continental Fan ECO-FLO Thru Wall Energy Recovery Ventilator. $700USD
Smart system that reacts to changes in air quality
broan-nutone.com/en-us/overture-hardware-detail
SmartVent Positive Advance is a centralised positive pressure system that constantly evaluates the environmental dynamics in and around your home. This 4-room system is suitable or homes up to 280m2 and is expandable to 6 rooms max. $3620NZD $4560 incl. Summer feature (Cooled air) SKU: SV04AD
Extractor fans 25 L/s AS 1668.2:2002
https://heattrans.co.nz/systems/
The Building Code (Clause G4) requires 5 percent of the floor area in opening devices or mechanical ventilation to achieve an air change in the occupied spaces (such as living areas) every three hours.
- Outdoor air supply shall be designed and equipment installed to comply with NZS 4303, or AS 1668.2 (excluding Table A1
- Where provided to remove moisture and other contaminants from kitchens, bathrooms, toilet spaces and laundries in household units, exhaust the air to the outside at flow rates given in AS 1668.2, Table B1 (flowrate not less than 50 L/s)
- Building interiors ventilated by mechanical systems incorporating filtration shall, except where Paragraph 1.4.4 applies, be maintained at a positive pressure.
- Remove exhaust air from the room mechanically at one third the inlet rate.
BRANZ recommendations
Should be built to an airtightness target of 0.35 ach @50 Pa and, preferably, should have mechanical ventilation as the default option. NZS 4303:1990.
bpcventilation.com/domus-aqh200-b for Guest wing £1400
Blower door testing to check airtightness. “It has to be under 0.6 air changes per hour.” The indoor temperature will be between 20 and 25 degrees Celsius year-round. @ 50Pa
Air Purification
AirTulip Sleep is the next-generation air purification system for the bedroom and beyond. This is an unmatched consumer product that uses a revolutionary technology called “laminar flow,” a unique method of airflow that doesn’t mix or contaminate air particles.
kickstarter.com/projects/1778384991/sleep-by-airtulip-have-a-clean-air-zone-right-in-your-bed $700USD +Freight
Hot Climates
Air travelling at 1m/s across the skin creates a perceived temperature drop of 3.6oc
Try to shade the exterior (Prevent heat ingress). Insulate well. Night time ventilation and airflow is good but is prevented by insulation. So thermal chimney drawing air from under the house (Ground source piping) on a timer.