HVAC sizing follow-up (aux heat, shared walls, sizing for heating, "runs all the time," etc)
TLDRThe video script addresses common misconceptions about heat pumps, emphasizing their efficiency and capability in cold climates. It clarifies the difference between power and energy, explaining that heat pumps can provide the necessary heat with less energy consumption. The speaker discusses the importance of understanding HVAC systems, especially the role of auxiliary heat and dual fuel systems as backups. The script also highlights the benefits of shared walls in townhomes for energy efficiency and counters the idea that heat pumps would constantly run at full capacity, explaining that modern systems modulate output based on need.
Takeaways
- 🌡️ Cold climate heat pumps are effective and efficient, even at low temperatures, debunking the myth that heat pumps don't work well in cold weather.
- 🔧 Understanding the difference between power and energy is crucial when discussing HVAC efficiency; the focus should be on the Annual Fuel Utilization Efficiency (AFUE) rather than runtime.
- 💡 Auxiliary heat, such as electric heat strips or dual fuel systems, provides redundancy and ensures heating even when the primary heat pump system fails or is insufficient.
- 🏠 Shared walls in townhomes or apartment buildings can improve energy efficiency by reducing the overall heating and cooling load.
- 🔌 Electric heat strips, while 100% efficient, may not be as energy-efficient as modern heat pumps, which can have a Coefficient of Performance (COP) greater than one.
- 🛠️ HVAC professionals should stay updated with the latest technology and industry advancements, such as variable capacity systems and inverter-driven equipment, to provide the best solutions to homeowners.
- 🔄 Short cycling is generally a concern with single-stage systems, but modern HVAC systems often have multi-stage or infinitely variable capacities to prevent this issue.
- 🌬️ Heat pumps can operate at varying capacities, running less frequently but more efficiently during non-design conditions, and only running constantly at full capacity during extreme conditions.
- 🔥 Furnaces and boilers experience thermal stress with frequent cycling, so modern systems are designed to minimize starts and stops for longevity and efficiency.
- 🌍 The future of heating and cooling is likely to be dominated by electric heat pumps, which are more flexible, efficient, and suitable for various climates, aligning with the broader trend towards electrification.
Q & A
What misconception is the speaker addressing about heat pumps at the beginning of the transcript?
-The speaker is addressing the misconception that heat pumps don't work in cold weather. They clarify that cold climate heat pumps are a thing and they work effectively even in low temperatures.
What is the common mistake people make when discussing HVAC efficiency?
-The common mistake people make is confusing power and energy, especially when discussing HVAC efficiency. The speaker emphasizes that it's not about how long the furnace runs, but about the Annual Fuel Utilization Efficiency (AFUE) and the ratio of energy released to energy consumed.
How does the speaker describe the role of auxiliary heat in a heat pump system?
-The speaker describes auxiliary heat as a built-in redundancy in the heat pump system. It takes over when the heat pump fails or when the temperature is too cold for the heat pump to provide the only source of heat. Auxiliary heat can be in the form of electric heat strips or a dual fuel system with a furnace as a backup.
What is the speaker's stance on having a backup power source for heating systems?
-The speaker advocates for having a backup power source, especially in areas with extreme cold. They suggest that even with gas heating, a generator can provide the necessary electricity to operate the heating system during power outages, and that having a space heater on hand is a good form of redundancy.
How does the speaker address the concern about heat pumps and power outages?
-The speaker points out that while gas furnaces may not work during power outages due to electronic ignition and other electrical components, having a backup power source can mitigate this issue. They also mention that modern heat pumps can still function with less power, typically around 400 to 600 watts.
What is the speaker's view on the future of heat pumps?
-The speaker is optimistic about the future of heat pumps, stating that they are more flexible, efficient, and suitable for all climates. They believe that heat pumps are part of the shift towards electrification and can lead to less electricity usage while providing more heat.
What is the speaker's advice to HVAC professionals regarding new technology?
-The speaker advises HVAC professionals to embrace and learn about new technologies such as variable speed blowers and electronic expansion valves. They warn that not keeping up with advancements can lead to competitors offering more modern solutions and gaining an advantage in the market.
How does the speaker explain the concept of short cycling in HVAC systems?
-The speaker explains that short cycling occurs when an HVAC system, particularly a single-stage system, runs for very short cycles. This can lead to poor dehumidification in the summer and increased wear on the equipment due to frequent stops and starts.
What is the speaker's clarification on shared walls in townhomes affecting heating and cooling loads?
-The speaker clarifies that shared walls in townhomes make the structure more energy efficient because they reduce the number of exterior walls that need to be heated or cooled. However, it does not mean getting 'free heat' from neighbors, as the heat transfer across well-insulated shared walls is minimal.
What is the speaker's response to comments suggesting that heat pumps would run constantly?
-The speaker responds by explaining that heat pumps would only run constantly at design conditions, and modern systems are designed to run at varying capacities based on the load. They also note that many systems are designed to never stop completely, as constant operation is better for the equipment's longevity and efficiency.
How does the speaker address the politicization of heat pumps?
-The speaker acknowledges the politicization of heat pumps and climate change skepticism but chooses to focus on the technical and practical benefits of heat pumps, advocating for their use regardless of political beliefs. They emphasize that heat pumps are a more efficient and cleaner way to heat homes, especially in areas with abundant nuclear power or for those who prioritize electrification.
Outlines
🌡️ Debunking Myths About Cold Climate Heat Pumps
The speaker addresses the misconception that heat pumps are ineffective in cold weather, emphasizing that cold climate heat pumps exist and function well. They share their personal experience with a heat pump during extreme cold and discuss the complexity of HVAC topics, particularly heat pump sizing. The speaker clarifies the difference between power and energy, explaining that the annual fuel utilization efficiency (AFUE) is what matters, not the runtime of the furnace.
💡 Understanding Power and Energy in HVAC Systems
The speaker clarifies the common mistake of confusing power with energy in the context of HVAC efficiency. They explain that a furnace's efficiency is determined by how much energy it outputs compared to what it consumes, not by how long it runs. The speaker also addresses concerns about gas furnaces during power outages and the need for backup power systems, as well as the importance of having alternative heating sources like space heaters.
🔌 Auxiliary Heat and HVAC System Redundancy
The speaker discusses auxiliary heat, which is a secondary heating system built into the main air handler to provide additional heat when needed. They correct their previous statement about using space heaters as a primary solution, explaining that auxiliary heat strips are a more integrated and reliable option. The speaker also mentions dual fuel systems as an alternative, combining heat pumps with gas furnaces for increased redundancy and efficiency.
🏠 Shared Walls and Energy Efficiency in Town Homes
The speaker explains that shared walls in town homes contribute to energy efficiency by reducing the number of exterior walls that need heating or cooling. They clarify that this does not mean receiving 'free heat' from neighbors but rather a shared thermal load that is distributed across the structure. The speaker also addresses concerns about heat pumps running constantly, explaining that modern systems modulate output rather than running at full capacity all the time.
🌬️ Variable Capacity Heat Pumps and HVAC Industry Evolution
The speaker discusses the evolution of HVAC systems, moving from single-stage to multi-stage and infinitely variable capacity heat pumps. They emphasize the importance of staying updated with industry advancements, such as variable speed blowers and electronic expansion valves, and adapting to new diagnostic tools. The speaker encourages HVAC professionals to embrace new technology to provide better services and competitive pricing.
Mindmap
Keywords
💡Heat Pumps
💡Efficiency
💡Auxiliary Heat
💡Dual Fuel Systems
💡Short Cycling
💡Shared Walls
💡Load Calculations
💡Variable Refrigerant Flow (VRF) Systems
💡Inverter-Driven Equipment
💡Politicization of Heat Pumps
Highlights
Heat pumps are efficient in cold climates and the notion that they don't work well in cold weather is outdated.
The confusion between power and energy is a common mistake that leads to misconceptions about HVAC efficiency.
The Annual Fuel Utilization Efficiency (AFUE) is the critical factor for gas-fired systems, not the runtime.
Heat pumps are becoming more versatile and efficient, making them suitable for various climates.
Auxiliary heat is a built-in redundancy feature in heat pump systems that can activate when the heat pump is insufficient.
Dual fuel systems, combining heat pumps with furnaces, offer flexibility and can use propane as an alternative energy source.
Local storage of propane could be a viable emergency power source for heat pumps, especially in cold climates.
Heat pumps can be more efficient than 100% because of their coefficient of performance, which can be greater than one.
Modern HVAC systems are moving towards variable capacity and multi-stage equipment, which prevents short cycling issues.
Heat pumps can be sized for heating needs without causing problems in the summer due to advancements in technology.
Sharing walls in townhomes or apartments makes structures more energy efficient by reducing exterior wall count.
Heat pumps are not expected to run constantly except during design conditions, and modern systems are designed to minimize starts for equipment longevity.
VRF (Variable Refrigerant Flow) systems are an advanced technology that efficiently redistributes heat within large buildings.
Heat pumps are politically charged, but their benefits for energy efficiency and reduced emissions should be universally accepted.
HVAC professionals must adapt to new technologies like variable speed blowers and electronic expansion valves to stay competitive.
Heat pumps should be the standard for homes with air conditioning as they can provide heat more efficiently than traditional gas heating.