Renovating a historic home is a commonplace occurrence. What is not commonplace is considering the “thermal envelope” of the historic home BEFORE renovations occur.

What exactly is a “thermal envelope”?

A thermal envelope includes everything on a house that shields the interior from the exterior elements: exterior walls, doors, windows. All of these elements contribute to having either a tight thermal envelope (good) or a loose thermal envelope (bad). A tight thermal envelope has little heating or cooling loss; a loose thermal envelope includes drafts and discomfort.

That being said, it’s important to consider that older homes were built during times when central heating and air were rudimentary or, in many cases, non-existent. Present day, we demand certain amenities that might be difficult to achieve in an older home. The major amenity we desire is a perfectly controlled indoor climate, no matter what the weather conditions or temperature is outside.

It is necessary to determine how to attain this ideal level of interior comfort before you renovate.

Here are some important considerations before renovation:

Find the Breaches in your Thermal Envelope

This involves doing a blower door test to find the breaches from the attic to the basement. This test determines where the leaks exist so that the house can be shored up, tightening the thermal envelope. Fixes include installing energy efficient/weatherproof doors and windows, enhancing insulation and adding air sealing to your house.

A common breach involves the Stack Effect (read our blog about this here), which is a very real problem in many of these historic homes. Essentially, this is the way air moves in and out of a building. Warm air rises, going out of the top of the house in the winter. While the warm air is moving out the top, cold air is pulled in through the lower floors. The summer brings the opposite effect: cold air falls to the bottom floors while hot air is sucked in through the upper floors.

2. Ductwork

As we stated before, historic homes were built during a time when central heating and air was not the norm. As a result, the ductwork in these homes can be too small, old and even leaky. Assessing the viability of your ducts before renovating is crucial to the future comfort of your home. A new HVAC system cannot operate with a faulty delivery system. Your HVAC professional can determine if your current ductwork can be salvaged, modified or if it needs to be replaced.

3. Furnace/Air Conditioner Size

After addressing all breaches to the thermal envelope, the homeowner needs to determine if the HVAC system is an adequate size to comfortably regulate the temperature in the house. Is it too small? Too large? A professional will be able to determine the best size for your house and your needs.

By prioritizing your comfort in your new space with the help of a HVAC specialist, you can stave off future problems that are hard to remedy once construction is complete.

At A.N. Roth Heating and Cooling, the most common problem they see is that they are not asked to get involved with a renovation until AFTER there are comfort issues. General Manager Richard Roth advises that if you don’t address your air sealing and balances before your renovation, “no air conditioner can help you.”

It is difficult to achieve a perfect “new construction” feel in an older home with respect to comfort levels. But with attention to ventilation and temperature which involves improving insulation, making your home energy efficient and air sealing throughout the space, an ideal temperature can be achieved and you can thoroughly enjoy your newly renovated space.

There are few things more miserable than the AC going out on a hot summer day. So how did folks cope with hot weather at home before the advent of the air conditioner? The answer’s simple: houses were designed a bit differently to better fit the climate and, most importantly, beat the heat.

The Shotgun House

Shotgun houses got their name from their layout—you could hypothetically shoot a shotgun through the front door and it would go all the way through the house and out the back door. One of the biggest benefits of these oblong houses was that they maximized airflow by allowing cross-ventilation through the lined-up doors and windows. This would flush out the stagnant, hot air while encouraging the flow of new, cooler air to help maintain a reasonable temperature.

Wraparound Porches

Wraparound porches not only provided ample space to gather, but also served as a solace away from the indoor heat. People would sit outside on their porches, enjoying the shade and the summer breeze. These porches also cooled down the air directly outside of the home, helping to ensure that the air that trickled in through doors or windows would be colder than the air radiating off of a sunlit porch.


Designed to improve ventilation, cupolas are small structures with windows or vents that sit atop a roof. The vents are angled downward so that the fresh air from outside filters in to provide oxygen for the people and animals inside. As the fresh air enters, heat and moisture escape, keeping things comfortable while also keeping wood and hay dry.

The Dogtrot House

A dogtrot house features a less common design that’s often associated with the South. These houses are distinguished by an open-ended passage or breezeway between two living spaces. The purpose of the hallway is to optimize airflow between the two areas—one being a living space and the other a kitchen or dining room.


Awnings are used not only for aesthetic purposes but also for providing shade, as they prevent sun rays from entering the home. While some sun is appealing, too much can cause the house to warm up to unbearable temperatures in the summertime. As an added benefit, awnings serve as a source of shade on your porch or patio as well.

Transom Windows

Dating back to 14th century Europe, transom windows are set in a horizontal beam above a door frame. In modern day designs, they are mainly decorative, but their original use was to provide ventilation while the door beneath was closed. This was ideal because air could pass through the windows while maintaining the security of the home.

Enter Modern Air Conditioning

Since Willis Carrier invented the electric air conditioner in 1902, home designs have opened up a bit, while transoms, awnings and other features that help keep a space cool have become less popular. Of course, that means when the AC goes out nowadays, things can really heat up inside. That’s where A.N. Roth can help. Since 1866, when Jacob Roth began selling and installing coal and wood-burning stoves, Louisvillians have come to rely on A.N. Roth Company for heating and cooling solutions for their homes and businesses. So next time you’re having HVAC issues, don’t hesitate to CONTACT US so we can bring comfort back home!

For many of us, winter means stepping onto icy floors with bare feet, walking through drafts, and cozying up near the vent to stay warm. This is because the majority of Americans heat their homes with forced central air, meaning that warm air is pumped throughout the house through ducts and vents.

Radiant heat is a more comfortable way to heat your home. Most radiant heat systems are underfloor systems meaning either hot-water tubes or electric wires are installed below the floor. This heating method eliminates uncomfortably cold floors, cold patches, and uneven temperatures.

image of hot water tubes being placed for underfloor radiant heating

Radiant underfloor heating involves laying electric wires or hot water tubing throughout the room.

Not sure what “radiant heat” is? Simply, radiant heat warms objects directly. Objects absorb thermal energy and then radiate heat to other objects. Radiant heat has been a popular method of temperature control for ages, from Roman hypocausts to radiators. With underfloor systems, thermal radiation rises from below, warming the floor, which in turn warms the rest of the room.

Ruins of a roman hypocaust.

Roman hypocausts were used to heat baths and other public buildings by circulating hot air under a masonry floor.

There are a lot of benefits to this kind of heating system. It is much more efficient than forced-air because it eliminates the loss of conditioned air from ducts. Underfloor radiant heating systems also use less electricity than other systems and can save up to 15% on energy bills.

Radiant underfloor heat eliminates cold spots and uneven temperatures!

Underfloor radiant heating is also more comfortable than other forms of heating. As thermal energy emanates from the entire floor, icy floors, cold patches, and overheating are virtually eliminated. Overall, radiant heating systems warm evenly, so it’s easy to maintain a comfortable temperature. Radiant heating also means better air quality. Unlike forced air systems, radiant heat does not recirculate dust and allergens.

Radiant heat is most easily installed in new construction projects, but it’s possible to install radiant heat in remodeling projects! If you want to learn more about radiant heating systems, contact us today!

A.N. Roth Heating and Cooling Named 2020 Inc.credible Awards Finalist

A.N. Roth Heating and Cooling was named a finalist for Greater Louisville Inc’s (GLI) 2020 Inc.credible Awards in the Small Business of the Year category. The 20th annual awards, presented by NuLease Medical Solutions, celebrate greater Louisville’s small businesses’ accomplishments and contributions to the community. Since 2000, the Inc.credible Awards have recognized more than 110 small, local businesses for their ongoing contributions to our community’s economic vitality.

We at A.N. Roth Heating & Cooling are incredibly proud to have been chosen for this honor. 2020 has been among the most challenging in our history of over 150 years. Being a small business means making sure that our employees feel appreciated, respected, and cared for through an unprecedented time for them and their families. It means working extra hard to make sure customers receive exceptional service, no matter what. We’re so thankful to be part of this thriving regional economy, and hope to be a Louisville institution for many years to come.

“We have seen that small businesses are the backbone of our regional economy,” said Sarah Davasher-Wisdom, President and CEO of GLI. “Despite the challenges our region faced this year, I have witnessed true resilience from our small business community. These finalists exemplify innovation, creativity, and passion for their crafts. We are thrilled to recognize these businesses that excel in pushing the envelope and bringing new ideas to our region.”

For the first time, the winners in each category will be announced on December 16th, 2020 at 3:30 PM during a virtual awards show.


About A.N. Roth Company (
Established in Louisville in 1866, A.N. Roth has been a trusted local heating and cooling company for five generations. A.N. Roth specializes in custom solutions to HVAC issues and utilizes the most environmentally friendly and efficient components in their state-of-the-art installations. To learn more, visit

About Greater Louisville Inc. (
Greater Louisville Inc. (GLI) – the Metro Chamber of Commerce is focused on growing the regional economy. As the region’s largest convener of business leadership, GLI leads economic and global outreach strategies focused on business attraction, nurtures the entrepreneurial eco-system, and champions the development of the community’s talent base. Additional strategic efforts focus on diversity and racial equity to help build a more inclusive economy. As the voice of Greater Louisville’s business community, GLI advocates for a pro-business environment and facilitates businesses engagement on issues that impact regional competitiveness. GLI is the 2019 national Chamber of the Year and is one of only three percent of chambers nationally certified with 5-star accreditation status by the U.S. Chamber of Commerce, based on GLI’s dedicated policy efforts, effective operations, beneficial programs and overall positive community impact. Learn about our investor benefits and connect with us on Facebook, Twitter and LinkedIn using @GLIchamber or visit


Louisvillians are moving forward and trying to establish their “new normal.” Even so, COVID-19 and air quality remain pressing health concerns. In public, we wear face masks and maintain social distance, but how can we improve the safety of our homes, schools, and offices? When it comes to improving indoor air quality, there are options from simple changes to large installations. These options range in price from completely free to several thousand dollars. If you’re interested in learning more about any of the options listed here, give us a call at 502-378-7366.

1. Improve Air Quality with a Whole House Air Purification System

The IQAir Perfect 16 can remove the smallest particles from the air.

In June we wrote a blog post about one of our favorite products: the IQAir Perfect 16 Whole House Air Purifier. This medical-grade whole house purification system has the highest possible air filtration rating. It must be retrofitted into your existing HVAC system. It removes not only 95% of particles larger than 0.3 microns, but it’s also 85% effective in removing particles above 0.003 microns (the smallest that exist). If you’re worried about small particles like fungi and viruses, you can’t do much better than the IQAir Perfect 16.

2. Get A Quality Air Filter for Your HVAC System

Getting the right air filter for your system is more important than simply getting the most powerful air filter.

Your home air filter is designed to keep your heating and air conditioning systems clean of dust and debris. It may seem like getting a more efficient air filter will automatically mean cleaner air. However, that can also mean reducing airflow. It’s also vital to change your air filter regularly. Many things can impact how frequently you need to change your air filter. For example, the age and location of your home, whether or not you have pets, how many people live there, whether any of them have breathing problems, and so on. Make sure to check your air filter regularly, because a high-quality filter can become useless if it gets clogged. Call A.N. Roth to learn what air filter works for your system.

3. Install A UV Sanitization Bulb

UV bulbs have no impact on particles like dust and dander. For that reason they are not a replacement for a good-quality and regularly changed air filter. However, UV bulbs significantly help with things like mold growth, bacteria, and viruses, as well as keeping your evaporator coil clean. It’s also possible to get a UV light product that eliminates odors, like this one from Honeywell. The installation can be expensive, and the UV bulb will need to be replaced yearly because it will degrade over time. While the initial investment may be pricier than you’d like to go, UV sanitation is great for active households, office spaces, and schools, and ultimately cost much less than a whole house purification system.

4. Utilize Humidification and Dehumidification Systems

Humidifier releasing steam

Keeping your home at the optimal humidity levels prevents mold and virus growth.

Depending on the season, the humidity levels in your home can change drastically. Using humidifiers and dehumidifiers can help regulate humidity levels to improve comfort and health. Ideally, indoor humidity should be between 30-50%. During winter weather, when outdoor humidity plummets, humidifiers prevent the spread of bacteria and viruses, moisten the air passages in our sinuses and lungs, and make our home more comfortable. Allergens like dust mites and mold thrive in moist conditions, and excess moisture in the home can damage wood floors, furniture, artwork, electronics, and even your home’s structure. During the summer when humidity increases, dehumidifiers are important to keep relative humidity below 50%.

5. Bring in Fresh Outside Air

According to the Environmental Protection Agency, indoor air can be significantly more polluted than outdoor air. Most homes have some degree of natural fresh air infiltration through cracks and small openings in the house’s structure and openings, but it’s important to bring fresh outside air into your home regularly. Whether by opening windows or doors or through mechanical means like outdoor air intakes.

Window showing clean fresh air

Bringing in fresh outside air is the easiest (and cheapest!) way to improve your air quality.

There are numerous ways to improve your indoor air quality, from something as simple as opening your windows more often, to something as significant as a whole-house air purification system. If you want to learn more about how to improve the air quality in your home, contact A.N. Roth Heating & Cooling today!

A.N. Roth Company has been a family owned Louisville business since 1866. Throughout our five-generation history, our commitment to excellent service for the people of Louisville has remained a constant.

1866 – 1897

Founder of A.N. Roth Company, Jacob Roth

The progenitor of the A.N. Roth Company, Jacob F. Roth was born in Bavaria around 1843. American immigration laws were laxer at that time, and as a young man with skills as a tinsmith, Jacob was a great candidate. While records from his life aren’t ample, we believe that with sponsorship from the newly founded St. Joseph Catholic Church, he was able to immigrate to Louisville around 1866. He set up his tinsmith shop near the church in Butchertown, and he called the business Jacob Roth and Company.

Alfred N. Roth, who ran the business from 1897 to 1944.

At that time, Jacob worked primarily with tin roofs and stoves, in addition to odd jobs as they arose. Early on, Jacob transported all of his materials and tools in a two-wheeled cart, so the scope of his business was limited by just how far he could walk. Jacob likely worked mostly in the Butchertown area and the East Market District (now NuLu.)

Jacob and his wife Henrietta Wiseman had two children: Alfred N. Roth, and Charlotte (“Lottie”) M. Roth. When he was old enough, Alfred began helping Jacob with the business. They graduated from a two-wheeled cart to a horse and buggy, which allowed them to expand the business throughout Louisville as far as Prospect. For larger projects far from home, Jacob and Alfred would take a tent and camp near the worksite until the job was complete.

1897 – 1945

In 1897, Jacob Roth was tragically hit and killed by a train on Story Avenue in 1897, leaving Alfred to take over the family business. Alfred and his wife Elizabeth had three daughters, Henrietta, Magdalena, and Marie, and three sons, Karl, Alfred (Alfie), and Frederick (Fritz).

The name changed to “Alfred N. Roth and Sons.” In addition to their work on tin roofs and stoves, Alfred N. Roth and Sons also made sheet metal products for clients like the Fischer Packing Company (now the Mellwood Arts Center) and the University of Louisville. They also expanded the business into hardware.

1945 – 1971

Alfred N. Roth

Alfred ran the business until 1945. His son Karl was in line to inherit the company as the oldest, but Karl insisted that the company be divided evenly between his two brothers and him. Now called A.N. Roth Co., the company began taking on larger jobs, like the HVAC systems in the French Lick Springs Hotel, the Ireland Army Hospital in Fort Knox, and the barracks at Bowman Field.

Karl P. Roth., Sr.

Karl primarily handled the estimating and scheduling, but he was also a true artisan. In addition to his HVAC work, he built stainless steel components for the packing industry and crafted copper tail boxes for big names in the bourbon industry. Over time, the company began to focus less on hardware and sheet metal, and more on heating and cooling services. The three brothers managed the company until 1971, when Karl’s son, Karl P. Roth Jr. took over operations.


1971 – Present

Karl Jr.

Karl Jr. brought outside experience to the business, having worked at Jim Edwards Company (an HVAC company) on Bardstown Road for several years. He also made it a point to get education from experts outside of the Louisville area. He attended frequent seminars and joined organizations like the ACCA (Air Conditioning Contractors of America) to get input, success stories, and perspectives from outside of his circles. In 1978, Karl Jr.’s sister Rose Mary also joined the family business.

A.N. Roth Company continued to grow, gaining a reputation in the city for HVAC expertise and customer-focused service. With the addition of Karl Jr.’s sons, Phillip III and Richard, A.N. Roth continues to keep on the cutting edge of technology. Always shifting to meet the demands of the market, A.N. Roth is now the Louisville-area expert on radiant heat and geothermal energy.

Richard, Karl Jr., and Phillip Roth III.

Less than 3% of family-owned businesses operate into the fourth generation and beyond. A. N. Roth Co. is proud to be among those select few, serving Louisville for over 150 years, and we plan to continue to provide superior products and services for many years to come. Over the years, there have been offers to sell our business, but we will always be family owned. The technology and the services that we offer may have transformed over the years, but we’ve never stopped following the essential tenets embraced by every generation of A.N. Roth: do the job right the first time, treat your team with respect, and always put the customer first.

Nothing is worse than leaving a restaurant smelling like food. Most of the time, smoke, heat, and intense smells are concentrated near the kitchen. But what if customers are making the food themselves, and cooking stations are scattered throughout the restaurant?