Tag Archives: infiltration

Proper Humidity Levels and Factors for Home Comfort & Health | HVAC Health

moist and dry air problems & health

Proper Humidity Levels and Factors for Home Comfort & Health – The Contents and Make Up of Air and Humidity

Proper Levels of humidity Factors for Home Comfort and HealthProper Humidity Levels and Factors for Home – Humidity is important to our home and health and it is important to maintain the correct humidity in our homes and workplaces for our health. What is humidity? Humidity is simply little water droplets in the air. Cold air is nearly saturated with these little water droplets because the contents of cold air allow the air to hold more water droplets or humidity. As air is heated it expands and holds less humidity. When you heat the air in your home using a furnace, boiler, or heat pump this air expands and becomes drier. It is air with less humidity relatively speaking before it was heated and compared to the outside air. Air that is 30° F with 80% humidity will only be 15% humidity at 75° F. That is a big difference in humidity levels in the home after the air is heated. Granted, you are not heating air from 30° F to 75° F with your furnace. Depending on the set up of your thermostat and heating system you are most likely heating air that is 68° F to around 70° F to 75° F depending on the thermostat setting. The point is unless you have a source providing humidity to the air stream you are simply reheating dry air from inside the structure. There will be minimal infiltration humidity but the infiltration humidity will never be enough to bring the humidity levels up to healthy levels inside the structure for the inhabitants, plants, and furniture.

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DDC Outside Air Economizer System | HVAC Control

DDC Outside Air Economizer System | HVAC Control  economizer dampers

DDC Outside Air Economizer System

DDC Outside Air Economizer System  – Outside louvers allow the DDC control system to open dampers and introduce fresh air into the building. Building automation system, or the energy management system as it is sometimes called, monitors outside air temperature and humidity and based on a calculation and opens the outside air dampers when this calculation determines a precise set point. Introducing outside air into the building not only makes common sense it is also required by the Mechanical Code in commercial applications. This is required mainly for health reasons as it rids the building of volatile organic compounds and CO2 which is naturally produced by humans. Large concentrations of CO2 can build-up inside the building and needs to be vented as too much CO2 negatively affects human health. It is therefore important that along with the intake of outside air into the building there needs to be an exhaust air damper to maintain good building pressure. Negative pressure inside a building is bad as it causes infiltration moisture issues which leads to mold and mildew. Too much pressure also creates its own problems so it is important, with an outside air damper system, to monitor and maintain building pressure. Enthalpy wheels add to the efficiency of a good economizer system.

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HVAC Home Ventilation and Home Pressure

HVAC Home Ventilation and Home Pressure

HVAC Home Ventilation and Home Pressure

HVAC Home Ventilation – It is becoming increasingly necessary to have your home checked for home pressurization. Does your home have a negative pressure inside of it? Do you have a gas or oil furnace which is inside the home and uses the air in the home for combustion air to fire the furnace or boiler? Do you have other gas or oil burning appliances, a fireplace, gas logs, or any thing which consumes air inside the home? This does not refer to furnaces which are located in the attic (unless you have a completely sealed attic or the attic has a maximum height of less than 30 inches.) These appliances consume air and along with some other air consuming appliances in your home the issue of home pressure and home ventilation come into question especially in this day and age when the drive is on to increase efficiency and reduce energy consumption. Homes are being built tighter with better insulation, doors, and windows. Less infiltration air is being fed into the modern homes of today so it’s important to give the home a safety check to make sure there is enough air left over for the occupants of the home.

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Indoor Air Quality | HVAC IAQ and Ventilation Basics

Indoor Air Quality – IAQ Basic Problems

Indoor air pollution can be reduced and possibly eliminated by taking corrective action using a defined plan. The first step is called an IAQ audit and often requires the services of both a HVAC Test and Balance (TAB) Company and an industrial hygienist. First of all it must be determined where the source of pollution is coming from and then steps taken to eliminate it. Vapor barriers and foundation sealant can often be the source of indoor air pollution but other areas need to be studied to ensure they are not allowing pollution into the structure. Other types of pollutants are carbon dioxide (produced by people), moisture, tobacco smoke, carbon monoxide, formaldehyde, ozone, and other volatile organic compounds (VOC’s) which cause issues with health and safety of the buildings occupants. After the source of the pollutants is determined then a plan of action can be implemented to ensure these issues are corrected. There are different levels of IAQ that range from very thorough to just a cursory look at the building and the buildings HVAC systems.

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SUNDAY, NOVEMBER 23, 2014

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