Introduction

Your building’s comfort is only as good as its HVAC design. 

Design is not just about what it looks like but about how it “works”.

When we think about Heating, Ventilation, and Air-Conditioning (HVAC), it is important to remember that an efficiently designed HVAC system offers comfort and also comes with the benefit of sustainability.

Attention to that, the NIST research report says that “improper installation of HVAC system could increase household energy use for space heating and cooling on the order of 30% over what it should be”.

That is because, every year, many projects suffer from HVAC design mistakes that lead to wasted energy and increased costs while creating a lasting impact on the building’s performance. 

This blog will highlight the 5 most common HVAC design mistakes and solutions to avoid them that you can keep in mind while offering HVAC design services to ensure that future installations are environment-friendly and cost-effective.

What is HVAC Design?

Let us understand HVAC. 

HVAC stands for Heating, Ventilation, and Air-Conditioning. These three major functions are interrelated with the need to provide required thermal comfort and acceptable indoor air quality. 

Whereas, HVAC design is a detailed engineering and planning of an HVAC system. It involves selecting, placing, and sizing HVAC equipment such as ventilators, ventilating fans, furnaces, and air conditioners.

The design process also includes aspects from MEP engineering design for the overall functionality of the HVAC system.

What are the Consequences of Poor HVAC Design?

Attention – The American Lung Association estimates that 50% of all illnesses can be linked to poor indoor air quality (IAQ). Don’t breathe contaminated, stagnant, humid air from a leaking or poorly maintained duct system!

1) High energy bills

High energy bills are the most concerning impact of mistakes/errors in HVAC design. 

When the system is not designed correctly, like it is too large or small for the space, it will work overtime while performing its job. 

A small unit will struggle to match it up with the space’s required airflow, while a larger unit will cycle on and off too often, wasting energy.

You can easily avoid HVAC design mistakes/errors by starting with a proper load calculation. Also, reliable tools are available in the market that can easily help ensure your system is the right size per your building needs.

2) Uncomfortable indoor temperatures

“V” in HVAC stands for ventilation, and ventilation is responsible for air circulation in the building.

Incorrect settings of the HVAC system lead to indoor air quality issues, resulting in uncomfortable temperatures, low humidity levels, and the spread of allergens and bacteria.

Next, air conditioners are natural dehumidifiers, and under normal conditions, air-conditioned rooms will be a bit dry if the rooms that start to feel cold and clammy are the result of improperly sized air conditioners. 

HVAC systems are equipped with blowers to maintain air circulation. However, due to HVAC system design mistakes, air starts to blow at high speeds, resulting in drafty areas and high air duct pressure.

Another mistake is unpleasant odors from within the air ducts. Regardless of the cause, because of this mistake, an HVAC system will continue distributing the smell throughout the building.

3) Health and safety risks

Common MEP design mistakes followed by poorly designed HVAC systems lead to compromised indoor air quality, allowing pollutants like dust, mold spores, and volatile organic compounds (VOCs) to gather in one place. 

This exposure can create respiratory problems such as asthma, allergies, and chronic obstructive pulmonary disease (COPD).

4) Shorter life of equipment

Overworking an HVAC system due to design errors puts extra “force” on the components, leading to breakdowns and a shorter lifespan for equipment like compressors, fans, and motors. 

This will further lead to higher maintenance costs and expensive repairs.

Importance of Understanding the Common Mistakes in HVAC Design

1) Savings on cost

Addressing errors like undersized equipment or poorly planned ductwork leads to costly retrofits or replacements. But by properly understanding MEP design principles during the planning phase, you can avoid such common errors in HVAC design while saving on huge energy bills and repairs.

2) Consistent comfort

The poor HVAC system will create an imbalance in temperature. This mistake can be avoided by understanding a well-designed HVAC system where you can improve air circulation and ensure healthier indoor environments.

3) Improved quality of air

HVAC ductwork design errors, such as sealed ducts or insufficient ventilation, can lead to the collection of pollutants and allergens in the air, negatively impacting health. 

However, the knowledge of efficient HVAC design and MEP system design helps you prioritize air quality through effective filtration and circulation.

4) Positive impact on enviromenent

Finally, understanding and implementing effective HVAC design practices positively impact the environment. 

Buildings can lower carbon footprint by optimizing energy use using efficient MEP systems.

Common Mistakes in HVAC Design and How to Avoid Them

1) Improper sizing of ducts

One of the most common HVAC ductwork design mistakes is improper sizing of ducts. 

To understand better, too small ducts can restrict airflow, causing the HVAC system to work harder and consume more energy. 

How to avoid – Conduct a detailed Manual D calculation to check and verify the appropriate duct sizes for your system.

2) Improper design layout of duct

A poorly planned duct layout will create uneven air distribution and hot or cold spots within the building. 

How to avoid  – Design the duct layout to reduce the number of bends and keep duct runs as short as possible.

3) Inefficient insulation

Insufficient insulation of ducts will cause energy loss and impact efficiency.  

Ducts that pass through unconditioned spaces like basements can lose a significant amount of heated or cooled air, resulting in higher energy bills and less effective temperature control.

How to avoid – The rule of thumb is always insulating ducts that run through unconditioned spaces.

4) Incorrect placement of vents and registers

Incorrect placement of vents and registers can lead to poor air circulation and discomfort.

How to avoid – Carefully plan the placement of vents and registers to ensure optimal air circulation.

5) Ignoring static pressures 

Static pressure is the resistance to airflow within the duct system. If not properly considered, high static pressure can reduce the efficiency of the HVAC system.

How to avoid – Measure and balance the static pressure in the duct system by understanding the manufacturer’s recommended range.

7 Tips for Proper HVAC Design

The first tip is identifying what will be needed when designing an HVAC system for a building.

Estimate building loads because it is essential to accurately determine how much heating and cooling capacity is needed to maintain a comfortable interior temperature.

When installing a new HVAC system, consider cost-effective plumbing design and electrical design solutions (components) that can handle the space’s load requirements and provide sufficient ventilation while saving power and energy.

Calculate the heat gain due to solar radiation and internal sources such as appliances and lights to size an HVAC system for your building accurately.

Develop a suitable air distribution system in your HVAC design.

Proper insulation is key to a well-designed HVAC system.

Choose the right MEP design firm that offers solar-powered systems and smart thermostats because they are becoming increasingly efficient and accessible.

FAQ’s

Conclusion

Edifice Expert’s HVAC design services ensure that your HVAC cooling and heating equipment runs efficiently and safely before installation.

That being said, utilizing our 15+ years of BIM expertise, we develop HVAC designs that are highly efficient, sustainable, and well-coordinated. Contact us for more details.