When you're designing an HVAC system for a custom home, every installation needs to earn its place. The mechanical system is no different.
Why the HVAC System for a Custom Home Is a Selling Point
The HVAC system for a custom home is one of the few places where we can put real money back in a buyer's pocket. Our whole premise is that a custom build drives a higher price per square foot, and that comes down to thermal comfort, fresh air, and acoustics. The HVAC system drives all three of those, which makes it one of our strongest arguments.
You can raise value with nicer finishes and amenities. We're doing that. On this development, we also want to put tangible money into our future buyers' pockets, and right now we have two ways to do it: The first is taxes. We're on a smaller lot, so our taxes are lower than the surrounding homes. The second is utility costs. Our goal is a 3,300 square foot house where the owners are only heating and cooling a fraction of it while living in a perfectly comfortable space.
That's a technical build, so we custom engineered the system around LG equipment, which gave us the flexibility to keep the house incredibly efficient and incredibly high end at the same time.
How a Dual Fuel HVAC System Handles Chicago's Climate
A dual fuel HVAC system has two heat sources. Ours pairs an LG electric heat pump with a gas forced air furnace, and the system decides which one is the better use of energy at any given moment. In Chicago's climate zone 5, with a 110-degree swing between summer and winter, that flexibility is the whole point.
On a mild spring or fall day, the heat pump is plenty. When we're in a polar vortex and it's below zero, we need something robust, and the furnace takes over. The system goes back and forth between the two on its own.
It also builds on the exterior wall assembly, which is designed to let water, vapor, and humidity move in and out intentionally.
What an Energy Recovery Ventilator Does for Fresh Air
An energy recovery ventilator, or ERV, controls the fresh air coming into the house. It brings outside air inside and tempers it on the way so the equipment isn't hit with below-zero or 100-degree air in any season. That means the system works less, uses less energy, and keeps utility bills down.
Without an ERV, whatever the air is doing outside is what comes through the ducts, and the equipment has to overcome it to hold 70-degrees inside. A standard system brings in air only for its own heating and cooling, and the only air going out is usually through bathroom fans and kitchen exhaust.
We chose a Broan ERV because it's automated, with synchronous ECMs, latent recovery, and auto balancing, so it monitors itself and adjusts all the time instead of sitting at one manual setting. It also plays nice in the sandbox with the LG equipment, and as far as I'm concerned, equipment that plays nice with other equipment is superior equipment. It exhausts all of our bathrooms too, so we skipped separate bathroom fans.
Why We Chose an 80-Gallon Water Tank Over Tankless
We went with an LG 80-gallon hot water tank in the basement, even though tankless units save space. The market demands five bedrooms and five bathrooms over $2M, and that means many people showering before school. A tankless heater is going to be a problem. The LG tank also helps control humidity in the basement.
Our basement is already tight from the foundation and drainage work. The tank runs on an air source heat pump cycle tied into the rest of the system, so it uses ambient heat from the basement to heat its water, and in return it gives the basement passive dehumidification and cooling. Are you starting to see how all of these pieces make the house work for itself?
Dehumidification and Air Quality Monitoring Close the Loop
A dehumidifier handles humidity on the days the system isn't heating or cooling, and an indoor air quality monitor keeps every piece working together. Ours are a Santa Fe dehumidifier and the Broan Overture IAQ monitoring system, and they're what let the house run itself without anyone thinking about it.
On a beautiful day in Chicagoland with the windows open and nothing running, people are still showering and living in the house. The Santa Fe dehumidifier handles that, and it integrates with the LG and Broan equipment without a fight.
The Overture system puts the period on the sentence. It's a separate system acting as a room monitor, watching everything and telling the system to respond if there isn't enough fresh air, if there's too much humidity, or if the air quality is off. We also tied in the kitchen. The range hood is from LG's Signature Kitchen Suite line, a commercial grade hood locked into the HVAC system, because the kitchen hood is where a lot of air leaves the house, and that air needs to be tempered too.
What It Adds Up To for the Buyer
My goal with this system is a house that takes care of the people and the things inside it. I think of it as a hypoallergenic house, where someone can bring in artwork or musical instruments and they'll be okay, and where a family dealing with allergies, or with wildfire smoke drifting down from Canada, has its own ecosystem inside. Their own bubble.
That's the pitch on the sale, and it's built into equipment buyers will never see. It also isn't cheap. In the end, we think it’s worth it. A little more attention to detail on the engineering and a lot more investment into the equipment will pay dividends over decades.
Watch how we put the whole system together in Episode 7 here. And if you're just finding us, start the build from the beginning in the Cultured Cottage Series on YouTube.
Frequently Asked Questions
What is a dual fuel HVAC system?
A dual fuel HVAC system uses two heat sources, usually an electric heat pump and a gas furnace. The system switches between them depending on the weather, using the heat pump on mild days and the furnace when it gets extremely cold.
What does an energy recovery ventilator do?
An energy recovery ventilator brings fresh outdoor air into the house and tempers it on the way inside. That keeps the heating and cooling equipment from fighting (or getting “zapped” by) extreme outdoor air, which saves energy and helps control humidity.
Is a tank or tankless water heater better for a five bedroom house?
On the Cultured Cottage, we chose an 80-gallon tank because five bedrooms and five bathrooms means a lot of people using hot water at the same time. A tankless heater can struggle when several showers are running at once.
Why does a custom home need a separate dehumidifier?
The heating and cooling equipment controls humidity only while it's running. A dehumidifier handles the days when the system is off and the windows are open, while people are still showering and living in the house.
Can an HVAC system raise a home's value?
It can, when it lowers utility costs and makes the house more comfortable. On the Cultured Cottage, the HVAC system is one of the main ways we're making the case for a higher price per square foot.