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Latest Product Roundup
Check out this versatile fresh-air-supply fan, durable masonry screws, a wildfire sprinkler system and more.
1 MIN READ
Indoor Air Quality
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Products/Tools
Versatile Fresh-Air-Supply Fan
1 MIN READ
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Products
Latest Product Roundup
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Products
Whole-House Air Quality
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Products
Fresh-Air Intake
1 MIN READ
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Products/Tools
Efficient Energy Recovery Ventilator
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Products/Tools
Single-Room Air Purifier
1 MIN READ
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How To
Practical Ventilation for a Warm, Humid Climate
14 MIN READ
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On the Job
Running a Bath Fan Exhaust Through Metal Roofing
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Tools of the Trade
Give Your Shop Vac a Mullet
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Tools of the Trade
Filter-free Air Scrubber
4 MIN READ
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Products/Tools
Smart Control Switch
1 MIN READ
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Products/Tools
Smart Airflow Control
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HVAC
Humidifying Homes
9 MIN READ
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Energy Vanguard
Box Fan Air Cleaner Update
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Energy Vanguard
Bad Advice About Indoor Humidity in Cold Weather
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Products/Tools
Energy Star Dehumidifier
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How To
Mobilizing for a Small Abatement Project
3 MIN READ
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Remodeling
Managing Asbestos During a Remodel
4 MIN READ
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Q&A
Pre-piping for Radon
2 MIN READ
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Products/Tools
Whole-House Ventilation Control System
1 MIN READ
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HVAC
How to Size an HRV or ERV
7 MIN READ
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Energy Vanguard
We Need Higher Ventilation Rates. But How High?
1 MIN READ
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Products/Tools
High-Tech, PM-Monitoring IAQ
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Products/Tools
Whole-House, Two-Stage Filtration System
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How To
A Troubled Tiny House
5 MIN READ
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How To
Health-Based Ventilation Rates
2 MIN READ![1. International Residential Code (IRC) ventilation requirements are calculated using the formula: [7.5 cfm x (number of bedrooms + 1)] + (sq. ft. x .01). 2 The ASHRAE 62.2 (2013) ventilation rates are calculated using the formula: [sq. ft. x .03] + [(number of bedrooms + 1) x 7.5 cfm]. This air-flow rate remains in the 2016 and 2019 versions of the 62.2 Standard. 3. Formula for Hayward Score (HS) recommended ventilation rates: 20 cfm x (number of bedrooms + 1) + [(sq. ft. - 1000) x 0.3]. a. Formula assumes 9-ft. ceilings b. Occupancy dictates ventilation rate for the first 1,000 sq. ft., then add 30 cfm per 1,000 sq. ft. (at 9-ft. ceiling height), as smaller volumes are quickly overcome by occupant CO2 c. It matters where you put the air: Bedrooms must get their 20 cfm per occupant, as healthy air at night is priority number one. d. As home square footage increases, two or more systems will be required. Focus on the "casita" (core area) first - the main bedroom and primary occupancy area, which includes the kitchen, baths, and home offices. As occupancy increases (families grow) additional systems can be added. e. Supply air to bedrooms, home office, living space, fitness/wellness room. Exhaust air from kitchen, laundry room, bathrooms and closets. Balance by zone. f. The Hayward Score (HS) recommendations assume stand-alone, balanced, energy-recovery ventilation (ERV), and are based on experience with high-efficiency ERV at 90% energy recovery and 60% moisture recovery with additional dehumidification where climate dictates. g. For best ventilation performance, consider the following: i. Design ventilation system to deliver HS recommended ventilation at 50% of capacity to optimize energy consumption. ii. In winter climates with increased levels of ventilation, supplemental humidification may be necessary to maintain 35-55% RH. iii. Installing a 4-inch MERV-13 filter in the main forced-air HVAC system can assist significantly in reducing dust and particle count indoors. It helps if the HVAC system is a variable-speed system that can operate continuously between heating and cooling cycles. iv. Infiltration air (natural leakage) is typically contaminated and needs to be diluted as well as cleaned. v. In the first two years after construction, chemical off-gassing from building materials and new furnishings is higher and may require running the ventilation system at higher than 50% operating speed. vi. Ideally the envelope of the house should be built to an air tightness of less than 2 ACH @50p. (Code maximum is 3 or 5 ACH, depending on climate.) It doesn't make sense for healthy, conditioned air to compete with infiltration air. Airtightness must be central to this discussion. This example that illustrates the importance of the envelope: A home built to airtightness limit of 3 ach @50Pa. has a natural leak rate (with no wind or significant temperature differential) of .17 ach - more than 50% of the air being introduced and conditioned by the ERV. 4. While four and five bedrooms are unlikely in these smaller houses, air-flow numbers have been provided here because the number of bedrooms often serves as a proxy for house occupancy. It is not uncommon for smaller houses to have 5, 6 or more occupants, and as we have learned human occupancy is a more important driver of ventilation need than house size.](https://jlconline.stg.zonda.onl/wp-content/uploads/sites/4/2021/hs-recommended-corrected.jpg?w=232)
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How To
A Builder’s Guide to Breathable Indoor Air
15 MIN READ
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Business
The Hayward Score: A Rating of Home and Human Health
2 MIN READ
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HVAC
Ventilation Code Simplified
2 MIN READ
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HVAC
Retrofitting Forced-Air HVAC With High-MERV Filtration
7 MIN READ
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Products/Tools
Smart Air Cleaner
1 MIN READ
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Energy Vanguard
Why IAQ May Be More Important Than You Think
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BUILDER
2021 Product Guide: Systems
4 MIN READ
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Centers for Disease Control and Prevention
Fighting the Coronavirus With Better Home Ventilation
1 MIN READ
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Business
Future-Proofing Your Business, Post-Covid Edition
1 MIN READ
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Remodeling
Seeing Through the Fog of Covid-19 Info
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HVAC
Seeing Through the Fog of Covid-19 Info
1 MIN READ