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Our Workshops in the News

One of our education program workshops was recently visited by reporter Mark Wedel of Second Wave – Southwest Michigan. He saw first hand how workshops provide opportunities to practice new skills.

In his interview of our Education Manager Jason Byler, he also captured the essence of how empowering our education program is. Our thanks to Mr. Wedel for spotlighting our good work and some of our participants. Click here to read the great story!

Should I Setback My Thermostat at Night?

Yes! Well, mostly yes. Well, it depends. About 99 percent of the time, setting back your thermostat at night will save you a substantial amount of money. The other one percent of the time is a much more complicated discussion, but worth looking into with these sub-zero temperatures we’ve been experiencing recently. This article is going to dive into the nuts and bolts of the matter to not only help you make informed decisions but also give you a solid foundation of how forced air furnaces work. So what do you need to know?

This article is for forced-air, natural gas or propane gas burning furnaces only. Some of this won’t directly apply to your house if you have electric radiant heat, a heat pump, geothermal, oil, or any other type of heating system in your home. Fortunately, most heating systems in Kalamazoo are forced-air gas systems. Not sure what type of heating system you have? Keep an eye on our workshop schedule for our next Heating Systems class!

I also want to point out that this article focuses on concepts and generalizations so that the average homeowner will understand what is going on with their heating system. If you are an expert in this area, please do not pick apart the article with things like latent versus sensible heat, how energy converts, density ratios, specific heat, thermal inertia, altitude, U values, etc. That being said, I am happy to write more articles in the future on specific aspects of these if anyone would like to know more. Feel free to post questions on our Facebook page.

The Basics of Heat

Before we can answer the thermostat question, we must understand what heat acts like, how heating systems are designed, and how homes are heated. The most important thing to remember right now is that heat moves from warm to cold, and the greater the difference in temperature between a warm area and a cold area, the faster the heat moves. The cold weather from outside does NOT come in to your home. The heat that is IN your home moves to the OUTSIDE.  When the heat leaves your home, the temperature drops inside.  There is actually no such thing as “cold.” Cold is simply a concept to describe the absence of heat.  Cold does not move – only heat moves.

Heat moves in three basic ways; convection, conduction, and radiation. We aren’t going to get into the differences between them right now although your furnace does use all three to move heat in your house, and heat leaves your house in all three ways.

Heat does not care which way is up. We often think and say that “heat rises.” Heat does not rise, but rather, warm air rises because warm air is lighter than cold air. This is an important concept to keep in mind because heat actually escapes your home into the cold outside from all sides, including through your basement. About a third of the heat lost in a typical old home is through the basement, while only about 10 percent is through the attic.

The way we keep heat from escaping from your house is with air sealing and insulation. One of the best insulators we know of is actually air itself. Different types of insulation – fiberglass, cellulose, spray foam, or foam board – do nothing more than trap air pockets inside it. It’s the air that is doing the insulating, not the insulation itself. BUT, and this is a big but, air that is moving is also one of the best ways to move heat. This is why air sealing is so important. Air moving through any type of insulation will move the heat out of your house at a very fast rate and make your insulation worthless.

Heat is a type of energy, much like electricity, light, or motion. Heat energy is measured in British Thermal Units (BTUs). The amount of heat energy stored in one cubic foot of natural gas is 1000 BTUs.  When you burn one cubic foot of natural gas, you release 1000 BTUs of heat energy, which heats up your furnace and is transferred into your home by the blower fan. Furnaces are sized according to BTUs; they most commonly range anywhere from 40,000 BTU to 120,000 BTU. When you get your bill from the utility company, they charge per MCF of gas used.  One MCF is equal to 1000 cubic feet, or 1,000,000 BTUs worth of heat. back to top

The Basics of Heat Loss and the Right Size Furnace

Now that we have a basic understanding of heat and how heat moves, let’s look at how we decide what size furnace to install in your home. If you install a furnace that is too small, it won’t be able to heat your home adequately in the winter. If you install one that is too big, it costs more money to run and your home becomes uncomfortable from drastic temperature swings (more on this in a little bit).

To “right-size” a furnace, we calculate the amount of heat that will move through every part of a house that is connected to the outside. This includes exterior walls, ceilings, doors, windows, basement walls, basement floors, crawlspaces, and any other place that has the outside on one side and the inside on the other. In addition, we calculate the amount of “air infiltration” that moves in and out of your home between the inside and outside.

This is done using the amount of surface area of a house component and the “R value” of the material to figure out how much heat moves through it.  We figure out air infiltration either by running diagnostic tests with a blower door, using a computer simulation model, or making an estimate from a chart based on how the home was constructed.  We put all of this information into a very large spreadsheet and calculate the total heat loss.

Now you are probably thinking “But wait! What if I build the exact same house in Florida as the one I have in Kalamazoo? You can’t say that the house in Florida needs the same size furnace!”

You would be absolutely correct. If you remember from the beginning of the article, the larger the difference in temperature between the inside of your home and the outside world, the faster heat will move to the outside. To account for this, we use what is called a “design condition.” Design condition is what mechanical contractors are required to use by the State of Michigan to properly size a heating system.

As a side note, if you ever replace your heating system in your home, be sure to ask the contractor for the “Manual J” calculations before hiring them. Manual J is the standard they are required to use to size your furnace. If they don’t have one or tell you that one isn’t needed, don’t hire them. Your existing furnace is NOT a good indicator of what size your new furnace should be. Rule of thumb, experience, or any other method they may mention is almost always wrong as well.

Design condition simply means keeping your home at 70 degrees when it is about as cold as it will get outside in your location. This is based on the 99th percentile of cold temperatures where your house is located. In Kalamazoo, this temperature is five degrees outside. Why did we pick five degrees for Kalamazoo when it’s below zero right now? This number is calculated based on the actual winter temperatures over the last 10 years. Ninety nine percent of the time, the winter temperature was above five degrees, and one percent of the time, the temperature was below five degrees.

We add all of this information to the big Manual J spreadsheet and we calculate the total heat loss of the home when it is 70 degrees inside and five degrees outside. This is given in the number of BTUs per hour the house will lose during that time. We then match that total potential heat loss of the home to the correct size furnace to have a “right-sized” heating system. This means when it is five degrees outside, the furnace will run nonstop to keep the home at 70 degrees inside. back to top

Why Not Just Put in a Super-sized Furnace?

By now, you are probably thinking that we could skip all of this stuff and just put in a great big furnace that will keep the house warm even when we have arctic temperatures outside. This is how it used to be done years ago and we find many very old furnaces in homes that are two or three times the size they should be. Oversized furnaces not only cost more to keep your house warm regardless of the outside temperature, they make you uncomfortable as well.

First, let’s tackle the comfort issue. A good analogy would be to imagine standing in front of a bonfire on a very cold night. When you face the fire, your front gets very warm and it feels nice but your backside is still freezing. You find yourself turning around over and over again in order to keep both sides of your body warm but you are never truly comfortable because you are too hot on one side and too cold on the other. Oversized furnaces work the same way. When they turn on, they send out a lot of heat all at once and immediately make the air warm in most areas of your home. They turn off very quickly and wait for the house to cool down before turning on again.

The sudden inrush of heat from the big furnace heats the air but not the furniture, walls, and other stuff in your home. Thermostats detect air temperature. This means that the furnace will turn off but the “stuff” in your house will still be cold. The heat from the air will move into the cold stuff in your home to warm it up causing the air to cool down quickly. This means the thermostat will then turn the furnace back on to heat up the air in your house again. This results in the furnace “cycling” on and off many times per hour, creating an up/down/up/down temperature swing and making the house feel drafty inside. The industry term for this is called “short cycling.”

The second reason not to oversize a furnace is that a furnace becomes more energy efficient the longer it runs. When a furnace first turns on, all of its parts are cold and the ductwork that delivers the air to your room is cold. The burning gas in the furnace must first be used to heat up all of this metal before it can move the heat to the air in your home. This usually takes about two to five minutes to happen. A furnace which is oversized might only run for five minutes before turning off again. This means that you are spending a larger amount of your gas bill just heating up the mechanical system in your basement and not in heating your living space.

So why did the industry decide to use a design temperature that only covers the heat load of a house 99 percent of the time? Remember that the furnace needs to be sized to handle really cold days, but not be too large for the warmer 30 degree days. The magic number to produce energy efficiency, indoor comfort for you, and make sure you are safe in case a polar vortex comes to town is 99, resulting in a furnace that is slightly smaller but more than up to the task. If it is below five degrees outside only one percent of the time, the outside temperature will not go too much below this for very long in most cases.  Even with the bone-chilling cold of negative 10 degrees in Kalamazoo over the last few years, it generally only happens at night and the temperature rises back up during the day. This means that the furnace will be undersized for only a few hours at a time and the inside temperatures will stay warm enough because of thermal inertia. back to top

Answer the Thermostat Questions Already!

Now we have almost all of the information we need to answer the question about setting back a thermostat at night. The simple answer to the question is yes, 99 percent of the time you should set back your thermostat at night to save money. In Kalamazoo, if it is more than five degrees outside, your properly sized heating system will have no problem bringing your home back up to temperature in a reasonable amount of time.

The complicated answer to the question is that one percent of the time you should not set back your thermostat at night, even though it would still save you money. Remember that if the temperature is five degrees outside, your properly sized furnace will run continuously to keep the inside at 70 degrees until the outside temperature rises again. If the temperature is four degrees outside, your furnace will run continuously and will keep the inside at 69 degrees. When it is 0 degrees outside, your furnace will run continuously and will keep the inside at 65 degrees. Of course, we know that the outside temperature doesn’t stay constant – the temperature typically drops at night and rises again during the day most of the time. If you go to bed at 10pm with your thermostat set at 70 degrees when it is five degrees outside, your furnace will continue to chug along to keep the temperature constant in your house.  However, if the temperature drops to -5 by 2am, the house will not instantly become 60 degrees. It will most likely be around 69 degrees inside at 2am. This is because the temperature outside doesn’t drop instantly and the inside of the house is already at 70 to start with. Because of thermal inertia, it takes time to lose the heat already in your house. As the night goes on, it may drop to negative 10 degrees for an hour right at sunrise and your house will most likely be about 67 degrees. Once the sun is up and the day warms, the temperature outside increases back to five degrees or more, and the furnace will be able to gain ground and bring the house back up to 70 degrees and turn off.

The thermal inertia in the house is why the temperature inside the home doesn’t drop as fast as the temperature outside of the home. This means that the temperature swings inside your house are substantially leveled out and most of the time you probably won’t even notice. back to top

So what happens when I set back the thermostat when it’s 0 degrees at night?

If you take the above scenario except that you set your thermostat to 60 degrees when you go to bed at 10pm, your furnace will turn off until the temperature inside drops to 60 degrees. The furnace is able to keep up with the 60 degree temperature all night, but you will have lost all of the thermal inertia in the home between the 60 and 70 degree marks when the furnace turned off at 10pm.  This means when you turn the temperature back up to 70 in the morning when it is negative 10 degrees outside, your furnace may not be able to get the temperature above 60 degrees until the outside temperature rises.  Once the temperature outside starts to rise, the furnace will slowly gain ground to get the house back up to 70 degrees.  This can take hours on a very cold day, and in some very cold stretches lasting several days, you may never get your house back up to 70 degrees until it is consistently above five degrees outside.  Your furnace ends up fighting a ten degree temperature rise instead of a three degree temperature rise had you not set the thermostat back at all.

This is all assuming that the furnace in your home is correctly sized.  If your furnace is oversized right now, then the five degree temperature may be much lower before it can’t keep up. If your furnace is undersized, then you may be in trouble when it is 10 degrees or warmer outside.  The only way to know the exact temperature at which you should not set back your thermostat is to either run a heat load calculation on your house or to experiment every time it gets very cold and track your results.

Go back to the beginning.

Seeking Technicians for our Repairs Programs

New job opportunities! (updated January 5, 2018)

We are seeking a qualified technicians to support our programs.

The full job description and application details are here for an HVAC Field Technician and for a Construction Trades Technician.

If you are passionate about serving others, working in a supportive team environment, and want to share your talents, we want to hear from you!

Save the Date! Furnace Fest 2016

Furnace Fest 2016 is Friday, September 23.

Save this link to check for updates.

2015 Fall Furnace Upgrade Program – Accepting Applications Now!

For the third year in a row, Community Homeworks is offering a special program to install high efficiency natural gas furnaces for 37 qualified low-income homeowners in Kalamazoo County.  Homeowners will be required to pay a $100.00 copayment at the time of application and commit to attend six (6) free education workshops at Community Homeworks. The program will run until the end of the year or until all available furnaces have been allocated. A high efficiency furnace will reduce energy bills by at least 15% and up to 50% in some cases.

Applications are now available at the Community Homeworks office at 810 Bryant Street, Kalamazoo, MI 49001. Applications must be complete when submitted in order to be considered.  Accepted applications will be processed on a first come, first served basis.

Participants must meet all the following eligibility criteria:

  • Own and live in a home in Kalamazoo County (home must be either owned or under mortgage) – other restrictions may apply.
  • Existing heating systems must be compatible with the new systems (natural gas, forced air system with ductwork). Accepted applications will include a site visit to assess compatibility.
  • TOTAL household income below 200% of the federally defined poverty level as defined below:

Weatherization Program Income Limits

  • Pay a $100.00 copayment at time of application. Ineligible applicants will have their copayment refunded.
  • Attend six (6) free education workshops (2 hours each) at Community Homeworks.

Documentation Required:  Completed application, proof of income, copy of the deed to your home, most recent copy of your Consumers Energy bill, and a check for the required copayment. If an application is not accepted, the check will be returned.

All work is done by Community Homeworks’ qualified and licensed mechanical technicians.

Thank You to Everyone Who Joined Us At Furnace Fest!

We couldn’t do what we do at Community Homeworks without the support of businesses and individuals who care about our community and want to help it thrive. Thank you to everyone who turned out and were so generous with your enthusiasm and support for Community Homeworks! We couldn’t do what we do without you. A huge shout-out to Brian and Dan and the whole Boatyard crew, to Joe Wang & the Test Pilots, to all our sponsors and auction item donors, to all our volunteers, and to all of you. What a great community we have here in Kalamazoo – neighbors helping neighbors!



Did you catch us on the Lori Moore Show?

In October, Development Director Kristina Nguyen again visits with Lori Moore, this time to go into more depth about our programs and services. Watch this video now.

In September, Development Director Kristina Nguyen and Boatyard Co-Owner Brian Steele had a chance to talk with Lori Moore about Furnace Fest and our partnership. Watch the video now.

Community Homeworks is Growing!

We’re very proud of what we’ve been able to accomplish with a small team over the last few years, but it is time to build up our capacity to keep responding to the needs in our community. We’ve just posted three new positions to expand our construction department:

Construction Manager: this new full-time position will manage, oversee, and evaluate the Critical Home Repair and Whole House Weatherization Programs for up to 200 families per year.

HVAC Service Technician: full-time position to assist in performing heating and water heater repairs as well as new installations of energy efficient heating systems.

Weatherization Field Technician: full-time position to assist in performing whole house weatherization, including air sealing, insulating, mechanical work, whole house testing, and other duties.

You can download full job postings from the links above – we are seeking qualified candidates who are committed to making a difference in Kalamazoo.


Little Library Build Day at Community Homeworks

Little Library Build Day at Community Homeworks

Little Library Build 4-11-15 (2)

With several stations set up for building, one station for power tools and one for a table saw to be used by trained experts only, there was room for everyone to get to work.

Community Homeworks was happy to host a four hour building workshop on Saturday, April 11, as part of the Little Lending Libraries in Vine project. By the end of the day, teams from Kalamazoo Collective Housing, Kalamazoo College, Oak Street Garden and Community Homeworks had built beautiful Little Library boxes ready to enhance their neighborhoods. Special thanks go to Hannah Knoll for organizing the event and to Little Library expert Tammy Wilson, KNHS construction supervisor Matt Milcarek, and Community Homeworks Executive Director Shaun Wright for providing technical supervision and expertise.

Bounlad Jones, a future Kalamazoo Valley Habitat for Humanity homeowner and a regular participant in Community Homeworks Education Workshops, helped design and build a Little Library that will go in front of her new home.   With the help of Tammy, Matt and Shaun, her Little Library evolved into something that is more “up-to-code” than any other Little Library we’ve seen. Complete with soffiting, asphalt shingles and full caulking, Bounlad’s Little Library is sure to keep her neighborhood books dry, and the brick-look exterior will look great with her new brick home!

Little Library Build Day 4-11-15 (5)

Matt and Tammy talk about the next step toward reaching Bounlad’s vision.


Little Library Build Day 4-11-15 (8)

Bounlad measuring shingles for her little roof.

Boundlad's Box (5)

Bounlad’s constructed box; we can’t wait to see her finishing touches!


Kalamazoo Community Foundation Grant Support for Whole-House Weatherization!

We are proud to be part of the Kalamazoo Community Foundation’s fourth quarter grant round – we are already putting this $60,000 grant to work. We have already completed four weatherization projects for low-income families in our current program year and have another 21 families with applications in process.

Are you wondering what it means to weatherize a home?
 IMG_20140819_162454It’s partly mechanical – installing new 95% efficient furnaces and water heaters certainly reduces energy usage and also reduces the risk of carbon monoxide poisoning. Proper attic insulation dramatically reduces heat loss, saving money and energy. Air sealing, not just doors and windows but rim joists and other gaps, eliminates drafts and further reduces heat loss.6737403523_5c75b3db20_o

IMG_20140819_162507Done properly, weatherization typically cuts energy usage and utility costs by 30 to 50% – that’s a big relief on a winter season gas and electric bill – and it produces safer air quality, more comfort and less stress for struggling family.

For more information about this grant cycle and our fellow grantee organizations, check out the great coverage in the Kalamazoo Gazette and on the Lorrie Moore Show.



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