A while back I posted about the problems many homeowners face with regard to areas of their homes that they simply aren't able to use very much they're not able to keep them at a comfortable temperature. I have a confession to make: I am one of those people -- or should I say, I was. I don't have a 4 seasons room, or even a 3 seasons one. I have a bonus room.
Bonus rooms, or my favorite acronymn used to describe them F.R.O.G (Finished Room Over Garage), are a somewhat newer phenomonon, but the concept is ages old: convert what would otherwise be unused and unconditioned space over a garage or other portion of your home into "living" space by insulating, drywalling and adding some kind of HVAC into it. My FROG is above the garage and is approximately 10 feet by 20 feet with sloped ceilings and a window at the end. With a young family we have turned it into a play room for the kids - an area of the house that the toys can live so we have some hope of keeping the bedrooms and other living areas approximately clutter free. There was problem, though - it was almost completely unusable because of the temperatures in the space.
When we first moved into our home we had a single furnace and air conditioner that served the entire home through a single duct system with a single thermostat located in the living room on the main level. There was a single 10 inch round duct that ran from the furnace into the attic where it split into a ductopus to serve the three kids' rooms, a bathroom, and bonus room. Thankfully we moved in late summer because the kids soon had relief from the 80 degree temperatures that were the best we could achieve when the days were warm. The solution for the kids was to increase the size of the trunkline to the second floor and add a zoning system with a thermostat located on the second floor. By adding the ability to sense the temperature on the second floor and direct cool (and warm) air there as needed we had reclaimed that living space (or at least didn't have to feel guilty making our kids sleep up there). The bonus room, however, didn't fair as well.
You see, for the most part, bonus rooms like their 3 and 4 season room breathren exist as a bit of an appendage on a home. As a result they are literally surround by heat load or loss surfaces that lead to wildly different heating and cooling requirements than anywhere else in the house. Think about this for a minute. The room you're sitting in right now more than likely doesn't have more than 3 surfaces that are losing heating (or gaining it, depending on the season). You probably have a wall or two and then either a ceiling or a floor that is touching the great outdoors or otherwise unconditioned space (attic, garage, etc). The rest of the walls, floors, and ceilings are likely shared with other rooms or conditioned spaces and represent no heat loss or gain in the room. So, when we have a bunch of these rooms touching each other and none of them has a terribly large loss or gain we can usually stay pretty comfortable with a single thermostat and a single duct system.
However, a bonus room has almost all of its surfaces touching the outside world. In my case I have a door and about 10 square feet of wall that is shared with my daughter's room. The rest is a floor over the unconditioned garage, walls that are touching a vented knee-wall attic, ceilings with the same, and a window to top it all off. What had the builder of our home done to accomodate what is a heat load and loss wildly different than the rest of the second floor? Two supplies of 6" flex that come out low on one of the walls and a single return. At least there is a return. Needless to say, it isn't nearly enough and even if it were, the system only runs when the 2nd floor thermostat calls for heating or cooling.
So, what's an HVAC guy to do when faced with a comfort challenge in his own home? I took my own advice and installed a ductless mini-split system. A ductless system is really the perfect fit for my application. I have a finished area that has wildly different heating and cooling loads that the adjacent areas, but it isn't really all that large an area that would require a completely seperate furnace and air conditioner. The model I chose to install is the Mitsubishi FE09 Heat pump. The system consists of an inside unit that mounts on the wall and an outside unit that houses the compressor. I chose to open up the drywall and run the refrigerant lines, drain, and control wiring inside rather than outside which made the project take a little longer but will result in a very high WAF (wife acceptance factor) when everything is done. The system is extremely efficient and provides both heating and cooling. Because it uses a variable speed compressor, the unit only runs as fast or slow as it needs to achieve the temperature. As a result the unit is also extremely quiete (watch this space for a video comparing this unit to our whole-house air conditioner).
The resuls of the project are almost unbelievably comfortable temperatures in the bonus room and we now have a space that we can truly use. We can now say that we have extra space that is a "Bonus" rather than a hot or cold room that we happen to store the toys in. Check out the pictures below for how it all turned out.
We can see the light at the end of the winter tunnel. There is still a little bit of snow on the ground from last week, but the warmer weather and rain from the weekend has almost erased all signs of winter from the landscape. The brown grass is just about the only evidence this isn't a late spring or early fall morning. So why am I thinking about heat exchangers? Well, we've been dealing with a lot of them recently and it has become obvious to me that there is a lot of confusion and misinformation when dealing with this subject.
As a homeowner, getting the news that your heat exchanger is cracked is a bit of a harsh blow. It's not unlike a doctor telling you about the "C" word. You know it's serious and you know you need to do something about it. Some people choose to live in denial of the seriousness of a cracked heat exchanger. They observe that their furnace is running just fine and was doing so before we arrived and will most likely continue doing so after we leave. The reality is that their furnace may be presenting a very real danger to their home and family and they need to address it before something terrible happens.
I'm not going to say that every cracked heat exchanger is a life or death emergency and that it is spewing levels of Carbon Monoxide into your home that can cause sickness or death. I am, however, going to say that every single cracked heat exchanger does need to be replaced, either through a complete furnace replacement or changing out the heat exchanger. If I can go back to my cancer analogy, you would never expect a doctor to say "Yeah, we found some cancer, but it's really in a non-critical area and you're feeling just fine, so we're not going to do anything about it. Go on living your life and we'll deal with this when it really becomes a problem." While you might not get rushed into emergency surgery to remove the offending tumor and surround tissue, you can be assured that there will be a treatment in your future. In the same way a cracked heat exchanger needs to be replaced, there is no repairing it and ignoring the problem simply isn't a solution.
So let's get back to basics for a minute here and talk about what a heat exchanger is and what it does. At its simplest level, a heat exchanger allows for the exchange of heat between two fluids without the fluids mixing. In the case of a forced air furnace, it is two different air streams, seperated by sheet metal or tubing that typically snakes back and forth to allow for the maximum amount of air to pass over it and the most heat to be exchanged between the two streams. Other types of heat exchangers exist in the HVAC world as well -- we can have refrigerant and air in an air conditioning or heat pump system, or air and water, like in a hot water boiler. The reason we want to keep the fluids seperate is obvious in the other examples - we don't want our refrigerant to leak out of an air conditioning system so we keep it within the coils and linesets and we don't want water leaking out of our boilers because that would be a hot mess. Why do we care about keeping the combustion air and house air separate in a furnace? What's the big deal, anyways?
Inside your furnace or boiler there is actually a fire burning, not unlike your oven. Natural gas or propane is being burned and the byproduct of that process is energy in the form of heat, along with varying amounts of water vapor, carbon dioxide, as well carbon monoxide, pure carbon (soot) and some Nitrogen Oxides (NOx). If you haven't already decided you wouldn't like those things to be in your house in any great quantities, let me tell you that almost none of them are desirable in large quantities in your home. With the exception of some additional water vapor in the home during the winter months, CO2, CO, soot, and NOx are certainly what I would call a pollutant and all of them can cause sickness or be fatal in high enough quantities. So why aren't we worried about ovens and stoves inside our homes? Two things - they aren't typically used enough or have a high enough output to worry about the levels they create and you're supposed to use a vent hood when you cook and bake. Everyone does that, right?
So why do heat exchangers crack in the first place? They're not supposed to, right? Heat exchangers are designed to provide safe operation of the furnace during its life expectancy - typically 15-18 years. However, there are many factors that can accelerate the wear and tear on a heat exchanger that they fail much sooner, sometimes in spectacular fashion. So what causes them to fail?
Sometimes it's just age and use. Where we live, furnaces see nearly 900 hours of use every winter. If we assume the average heating cycle is 15 minutes long, that heat exchanger is heating up and cooling down over 3,000 times per year. Try this experiment - take a paper clip, stretch it out and see how many times you can bend it back and forth before it breaks. So, sometimes heat exchangers just wear out with time and age and need to be replaced with a new furnace. Some times that's 15 years, sometimes it's 20 and sometimes they never crack and have other expensive repairs or the efficiency gain is enough to warrant replacment.
More commonly, the cause of a cracked heat exchanger is misapplication or poor maintenance of the furnace. All too often, furnaces are grossly oversized or used incorrectly which causes the heat exchanger to fail prematurely. Think of our paperclip example again. This time fold it completely in half for each "cycle" and see how many times you can do it. I promise you it will be far fewer times. When a furnace is oversized, a number of problems can exist including short cycling and cycling on limit. Both of those cause the heat exchanger to heat up and cool down far more often than if the furnace was closer to the proper size for the home or, better yet, was able to use a lower stage or modulate its heat output for smaller loads.
Another heat exchanger killer is airflow, or more specifically, a lack of it. The primary cause of low airflow in a furnace is a dirty filter. It can be hard to remember to change that filter or at least check it every month (which is why we recommend an air cleaner that can go for much longer without changing) If your filter gets clogged up with dust and dirt and the air simply can't get through, your furnace will cook itself to death. The heat simply won't be able to get out and the furnace will likely cycle on its high limit until it ceases to function or you change the filter. Meanwhile, your heat exchanger will go through a lot of stress when it is constantly overheated and cooled back down. Lack of airflow also leads to much longer heating cycles so not only is the heat exchanger hotter than it needs to be, it also has to endure the pain for a great time.
Sometimes it's easy to see the crack in the heat exchanger and understand why it's a problem, but what about when cracks are just forming or what if it doesn't seem like it's a critical area of the heat exchanger? It is our opinion and one shared by the American Gas Association (AGA) and AHRI that any crack, hole or other failure of the heat exchanger is reason to replace the heat exchanger or the unit. Sometimes the cracks like to hide like these:
But we can see why these are a cause for concern when we simply shine a light inside the heat exchanger and see this:
Our recommendation on finding a crack in a heat exchanger will always be to replace the heat exchanger or the furnace it is in because your family's health and safety is far too important to make guesses and assumptions about how dangerous this crack may or may not be. It's like the doctor that finds cancer - it might not be good news, but it needs to be shared and dealt with.
If you would like to have your furnace inspected and cleaned it's not too late in the season. Head over to our Specials page for money saving coupons too.
February 25, 2013 (ANTIOCH, Ill.) (WLS) -- Four people are recovering after apparently being overcome by carbon monoxide fumes in far north suburban Antioch.
That's how the story begins and unfortunately is seems all too familiar. Just a month ago we saw this:
January 28, 2013 (CHICAGO) (WLS) -- A family was in mourning Monday after an apparent carbon monoxide leak in a West Rogers Park building killed two women and sickened seven people.
What do these two stories have in common, besides both being in the Chicago area within a month of each other? The cause of the CO poisoning
The fire department says the source of the carbon monoxide poisoning came from a boiler.
"What we find out is that carbon dioxide was leaking through the boiler and that caused the problem," Ahmed said.
So what can we learn from these stories? I think the first thing to note is that Carbon Monoxide poisoning is very real and life threatening. With symptops that mimic the flu, you might not even realize you're being poisoned by something in your home.
In at least one of these stories it is specifically noted that the home did not have a Carbon Monoxide detector, which is the law in Illinois and should be something found in every home. For less than $50 you can at least give yourself an alert when levels are elevated. The level in the Antioch home was 600 parts per million. CO becomes dangerous starting at 35 PPM and can be fatal at 100 PPM.
What else can we do to prevent these kinds of tragedies? Get your boiler or furnace tuned up by a professional technician every year. This will not only make sure everything is in good operating order to greatly reduce the chance of CO poisoning, but they also help improve efficiency, and reduce breakdowns in the heating equipment we depend on through the winter.
Part of our Precision Furnace Tune-up is a Heat exchanger safety inspection. The heat exchanger is the part of your furnace or boiler that is responsible for keeping the combustion products (including Carbon Monoxide) seperated from the air in your home. If that part of your furnace becomes compromised by a hole or a crack, you could find yourself in a situation not unlike the folks in the stories listed above. Making sure your furance is safe and reliable are our top priorities when we work on your equipment. After all, this could be your lives at stake as we see in the recent news.
I'll leave with this parting thought: if your furnace or boiler was a car driving at 60 miles an hour, it would drive over 50,000 miles per year. You would definitely have your car checked out at least every 50,000 miles - probably get the tires changes and the oil and filters too. Make the investment in your peace of mind and get your equipment checked out today.
It wasn't that long ago that we met the Frankenbeast. It was a story of misapplication with good intentions and bad information. The other day, I met Frankenbeast's big brother. I'll call him Cerberus.
At least this time we're in a commercial application where twinning might actually make sense. In this case we have a large room served by a single ductwork system with (2) 5 ton air conditioners. Those 2 air conditioner coils sit above 3 furnaces with 90,000 Btu/h input, 95% efficiency, and 3 ton capable blowers.
Can you guess what the problem might be? That's right, airflow. Amazingly, I'm told that they didn't have a problem with the air conditioners freezing up. The furnaces have not been so lucky. Because of that 10 inch tall shared plenum above all the furnaces and the blocking plates and AC coils and everything else going on here, the heat is having a little trouble actually getting out of the furnaces and inevitably, 2 of the 3 go off on high temperature limit within minutes of firing up.
So, what to do? This is obviously not going to work in its current state, but how do we get to a reliable, sustainable solution without breaking the bank? After all, these furnaces aren't even 2 years old yet. Like so many times, it starts with figuring out what we actually need to get out of this system to satisfy the heating and cooling needs of the building.
I won't go into the gory details of what is needed to correct this problem, but I can tell you that it is neither cheap nor easy. We can't just move to using two of the furnaces because they can't drive the cooling need for the space so they'll need to be replaced with larger units. The coils are hooked up to very old air conditioners using R22 that has become very expensive. In this instance the recommendation would be to replace both the furnaces and the air conditioners to make it a sustainable and efficient solution. Unfortunately in this case, it will be paying twice to have it done right because it wasn't done right the first time.
I don't believe this is a case of a contractor intentionally trying to put together a system that doesn't work - I believe it is a case of a contractor trying to put together a system for as little money as possible without knowing how much heating or cooling was really required for the space and unfortunately the customer is the one that ends up paying for it - literally - in the end.
I went through an interesting exercise the other day and the results were really eye-opening for me and I wanted to share them. Just about all of us get the pleasure of paying an electric and gas bill every month and most of us are aware that our heating and air conditioning is responsible for a large portion of that bill, especially when it's hot or cold outside and the systems get used a lot. We try to save money by setting the temperature inside lower/higher, open windows, wear sweaters... the list goes on and on. But do we really know how much we're spending? I didn't and some of the work I was doing for a customer to investigate his actual cost lead me to investigate my own as well.
The method I used isn't one that was taught to me or standardized by any organization that I know, so take it with a grain of salt. Its not particularly scientific and any similarity to any other method is purely coincidental and I will certainly give credit if someone else can point out where this has been used before. That being said, here's the issue: we all pay utility bills every month and I'm sure most of us would like to see them get smaller, but where do we start? Are we paying more than we need to for HVAC operation? Do we have other energy users that are costing us? How do you know?
The challenge that I faced was seperating heating and cooling costs from other costs in our homes. Things like lights, water heaters, washers, dryers, refrigerators, computers, etc. all use the same electric and gas that our furnaces and air conditioners use, but we only get one bill. I needed to start with a basic assumption that there are times of the year that we use little to no heating or cooling and we can find what I call the baseline months for electric and gas usage. Those months are typically going to be in the Spring or Fall and they're going to be the lowest usage - gas for heating and electric for cooling - of any in the year. Within reason, we can assume the electric and gas costs for these months are going to be everything other than heating and cooling costs (with a little extra thrown in for those occasional hot or cold spells). Once we know what the baseline usage is for our house, all we have left to do is subtract the baseline amounts from the remaining months to leave us with the cost of heating and cooling. An example is going to help clear things up here:
What you see there is a year of data from my gas and electric bills. You can see my gas baseline is in August (which makes sense) and my electrical baseline is in October (not in December or January because we have to use an electric heater in our Bonus Room to make it comfortable). I then subtracted those from all the months to reveal how much Gas and Electric were used to heat and cool the house all the other months. What we end up with is $577 of gas and $428 of electricity that was used to heat and cool my house. Everything that was left - $150 in gas and over $1,200 in electricity were consumed by other energy users in the house.
I was fairly confident that my assumptions were reasonable, but I wanted to double check myself with the tools I have available. What I did next was to apply the calculated heating and cooling load for my house and load that information into a HVAC design program. The results were interesting:
If we subtract the water heating cost we get a total of $975 per year for HVAC costs. The actual costs were $1004 and we had a very hot summer. Overall I'm pretty happy with how close the estimates were and it really opened my eyes to the fact that I have over $100 a month in electrical costs that isn't air conditioning! (Time to turn off those lights and computers when they're not being used).
On a parting note - remember that customer I said I was working with? He has a Geothermal system that we installed for him last year. In a house that is twice as big as mine he's going to be spending less heating and cooling it. As long as he can keep his other gas and electric use under control he's going to be in great shape.
If you find that your Heating and Cooling costs are out of control or just want to find out what they actually are, give us a call or contact us using the link above. You might be surprised just how much you're spending and how much you stand to save.