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"We are the third generation of my wife's family who have dealt with Custom Vac for our heating needs and Ramona and I are happy with the service that they provide. Over the years they have installed two furnaces, one electric and one mid efficiency oil furnace as well as conducting annual maintenance checkups and ductwork cleaning. In all cases we have found them to be professional, courteous and diligent."
Chris Beckman and Ramona Mohr
Trends in housing Part 2
Building Trends, How to Avoid Trouble, "The House as a System"

Part Two of a Two Part Series

There are many new trends changing the way in which homes are built and renovated. Each an improvement on its own, but when combined, can lead to problems.

In part one we spoke of the first five trends to help you avoid trouble and explained "The House as a System", this time we will cover the last five trends and offer solutions in a brief chart.
  1. Fewer return-air inlets - Duct systems that are not properly designed and installed can create pressure imbalances within the home itself. We often find homes with no return air from bedrooms or high wall returns but no low wall returns, these all can create problems. Placement of registers and grilles plays and important role in a good system and may require some forward thinking of placement of furnishings, and window dressings. Another important consideration is the number of return air grilles and the total volume of air required by proper duct design.

    A common problem that we find is not enough return air. In simple terms if a system requires 1000 CFM of supply air to condition a home, there should be at least 20% more return air coming back to the appliance or a total of 1200 CFM. This will allow for changes in normal living conditions. Because, at some point one or more return air grilles may become blocked by a piece of furniture. We don't live in a perfect world. Even when we place registers and grilles in proper locations and do all the right things someone finds that new piece of furniture using up the space blocking the grille.
  2. Higher comfort system air flows - As we said earlier, airflows from blowers (fans) in today's comfort systems can produce between 800-2000 CFM of air. This can be as much a ten times more air than that of an old gravity system with no blower, and one to two times that of a 30-year conventional gas furnace. It is important to ensure that the ductwork can handle the increased airflow, while, maintaining proper velocities.

    Higher airflows and increased velocities over the cooling coil and through the furnace can cause a loss of comfort, increase energy use and decreasing efficiency. So too, can low airflow have the same adverse affects. Studies show that improper airflow and setup can reduce efficiency, comfort and shorten equipment life. It is important to ensure that any increase or decrease in total airflow volume and velocity are taken into consideration as "The house as a System".
  3. Newer construction techniques, framing and assemblies - With advancements in technology come new products and many offer us increased living space, fewer walls, more open concepts (great rooms) and lots of windows. The industry is using more engineered (webbed) floor trusses and laminated floor joists. If we are to utilize these spaces for the return air, how will they be made airtight? Can they be made airtight? Interior walls in some cases are utilizing steel studs, how can they be made air tight with all the holes that are manufactured in them for wiring and piping?

    Basically, we are loosing our ompartmentalization structures that we once used. If we do not address this properly, it is possible to loose airflow, create pressure imbalances within the home (room to room), loss of comfort and increased energy use. This is an area that with all the new building techniques being applied can be missed if not looking at the "House as a System."
  4. Over-sizing of appliances, bigger is better - Huh! Huh! Huh! A common phrase used by everyone's favorite home handyman, Tim (the tool man) Taylor. Tim epitomizes the average person who believes that bigger is better. The trends in housing have been tighter homes, better windows (triple pane) and higher levels of insulation. Yet, we have and continue to see over-sizing of comfort cooling systems. Undersized ducts, too big of a furnace, too large an air conditioner results in increased moisture levels in home, poor heating and cooling to all areas of the home due to short cycling of the equipment. The results are mold, mildew, rot, high-energy bills, decreased comfort and additional expense to retrofit.

    One job that I can speak about was a home built in 1950 that had a 140,000 BTU oil furnace installed. In 1977 the furnace was changed out to gas and a 130,000 BTU mid-efficiency furnace installed. In 1987 an 80,000 BTU high-efficiency furnace was installed. In 1998 a 60,000 BTU two-stage variable speed high-efficiency furnace was installed. This present furnace operates at 37,000 BTU on low fire (first-stage) for approximately 75-80% of the time. This home like many continued to have renovations done over the years, such as basement insulation, new windows and attic insulation.

    What this average home proves is, we do make our homes tighter and that over time we need to assess "The House as a System" to ensure that all the interactions and relationships are still in harmony with each other. Yes, there is a price to pay for this. But, what price would you pay for a good nights sleep, a day that you could no longer hear the comfort system start and stop, or know that the fireplace would not harm you and your family every time you use it?

    Having a proper EnerGuide for Houses home energy audit can give you and your installer the correct information and will assist in the proper selection and design of a comfort system that will meet your needs.
  5. Home offices - We saved the best for last. Home businesses, home offices are on the rise. We have all chosen lifestyles that have driven this trend. As workers we are insisting that we have more time for friends and family while maintaining a career. We are asking for more flexibility. More women than ever are entering the workforce. Employers are more flexible as well because they are faced with a shortage of skilled workers. As such, businesses are becoming very creative and flexible. According to the Home Office Association of America there are approximately 11 million telecommuters (those who work one-to-three days at home) in the US today.

    According to Business Week (April 6, 1998) between 1991-1997 the number of wage and salary workers who received pay for work at home doubled, from 1.9 million to 3.6 million. What we can say is that we have and will continue to see an increased move to home offices. We are seeing more stay at home dads who are raising the kids while working from home. What does all this mean? Well it means that there will be an increase in exposure to indoor generated pollutants such as moisture, chemicals, more localized heat generation and higher energy use to mention a few. The increased moisture being placed into the space due to the home being occupied all the time, more cleaning, washing and simply occupant exhalation (breathing). More localized heat affects individual comfort.

    Computers, photocopiers, printers, scanners, radio's and televisions, all produce heat and can be found in many small home offices. How do we deal with all that localized heat? How do we add additional ventilation to this area? Do we need to provide this level of comfort 24-hours a day or only when the home office is occupied? The chemicals emitted from the printer and photocopier needs to be vented outside. Will we have enough make-up air? Will the vented appliances back draft?

    We have seen a dramatic increase within the industry in the numbers of higher end air filtration and whole-house ventilation systems. As homeowners spend more time in their homes they realize that something is not right. Symptoms may be that they feel tired all the time or that they don't feel the same as they once did within the home. They may notice that when they are out of the home they begin to feel better. What they do know is that something is wrong and cannot pinpoint the cause(s). "The House as a System" needs to be taken more seriously than it has in the past. With home offices becoming one of the largest trends within homes the potential for problems increases.
The Ten Trends in Review





Tighter homes

Insulate right, control building pressures and install ventilation.


More vent-free or vent-less fuel burning appliances

Eliminate vent-less and vent-free burning appliances; ventilate cooking appliances.


More exhaust fans and devices

Seal and tighten house from attic and/or crawlspace, and add measured flow to make-up air to offset pressure imbalance.


More higher efficiency appliances with lower vent and chimney temperatures

Remove and/or de-couple appliances from house air. If necessary, install sealed combustion appliances.


More Forced air systems

Seal all ductwork and plan for the installation of a mechanical ventilation system.


Fewer return-air inlets

Ensure house and ductwork are sealed, airtight, and insulated properly, and that the appliances are sized correctly.


Higher comfort system air flows

Ensure that ductwork and equipment are properly sized and make changes to airflow or ductwork to meet with the manufacturer’s installation instructions.


Newer construction techniques, framing and assemblies

Block and seal all wall, floor and ceiling cavities or assemblies used to distribute air and if necessary change traditional ductwork practices to meet the new change in building construction.


Over-sizing of appliances bigger is better

Properly size the comfort systems (heating, ventilation, and air conditioning) HVAC appliances and assure insulation is installed properly and that building envelope is airtight. Consider having an EnerGuide for Houses Program, home energy audit on your home. Call participating contractors for information.


Home offices

Install mechanical ventilation and assure all home office use and future usage trends are considered and designed.

These ten trends outline how "The House as a System" is affected and what can be done to correct problems. It also, stresses the point that every homeowner should work closely with their builder, renovator, contractor and technician to ensure that all their needs are being met. This two-series piece was developed as a means of raising points for discussion and to ensure that homeowners understood the complexity of their home and the interacting relationships that exist.

In addition, many homeowners call and ask contractors for prices for installation of equipment over the telephone. This is never really possible and we hope that when homeowners look for a contractor, they select one to three reputable companies who can conduct a thorough site visit and prepare a detailed written proposal.

In closing, don't be afraid to ask for referrals and follow up on them. Reputable companies will never be afraid to give you references.



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