About HVAC Solver
HVAC Solver is a comprehensive free resource for homeowners and HVAC professionals. We provide engineering-grade calculators, troubleshooting guides, efficiency ratings explained, and reference data—all based on real engineering standards from ASHRAE, ACCA, DOE, and EPA, not marketing copy or opinions.
What HVAC Solver Offers
Our website covers every aspect of residential HVAC systems, organized into comprehensive resource hubs. Whether you're sizing a new system, troubleshooting a problem, understanding efficiency ratings, or comparing energy costs, we have the tools and guides you need.
HVAC Calculators Hub
Our calculator collection includes over 25 interactive tools for sizing, cost estimation, and system design. Every calculator uses methodology from ASHRAE handbooks, ACCA Manual J and Manual D, DOE test procedures, and industry-standard formulas.
System Sizing Calculators:
- AC Tonnage Calculator — Size your central air conditioner using Manual J methodology
- Heating BTU Calculator — Calculate furnace or boiler sizing based on climate zone and home envelope
- Heat Pump Sizing Calculator — Determine heat pump capacity with balance point calculations
- Mini Split Sizing Calculator — Size ductless mini-split systems for single or multi-zone applications
- Room AC BTU Calculator — Size window or portable air conditioners for any room
- Furnace Sizing Calculator — Calculate furnace output requirements for your home
Water Heater Sizing:
- Water Heater Sizing Calculator — Size tank water heaters using First Hour Rating method
- Tankless Water Heater Size Calculator — Determine GPM and BTU requirements for on-demand water heating
Airflow & Ventilation Calculators:
- CFM Calculator — Calculate cubic feet per minute airflow for any application
- Duct Sizing Calculator — Size HVAC ducts using ACCA Manual D methodology
- Bathroom Fan CFM Calculator — Calculate exhaust fan sizing for bathrooms
- Air Changes Per Hour Calculator — Determine ventilation rates for any room
- Air Purifier Sizing Calculator — Size air purifiers using AHAM guidelines
- Ceiling Fan Size Calculator — Choose the right ceiling fan diameter for your room
Energy Cost Calculators:
- AC Running Cost Calculator — Estimate monthly air conditioning electricity costs
- Electric Heater Running Cost — Calculate space heater operating costs
- Heat Pump Running Cost Calculator — Estimate heat pump operating costs by COP
- Heating Cost Calculator — Compare heating costs across fuel types
- Dehumidifier Running Cost — Calculate dehumidifier electricity usage
Conversion & Reference Calculators:
- BTU Conversion Calculator — Convert between BTU, watts, kW, and tons
- COP Calculator — Calculate Coefficient of Performance for heat pumps
- Sones to Decibels Converter — Convert between sones and decibels for fan noise
- Dew Point Calculator — Calculate dew point from temperature and humidity
- Generator Sizing Calculator — Size backup generators for your home
HVAC Troubleshooting Guides
Diagnostic guides that help you identify HVAC problems before calling a technician. Each guide covers symptoms, causes, DIY fixes, and when to call a professional.
Air Conditioning Problems:
- AC Not Blowing Cold Air — Diagnose why your AC isn't cooling
- AC Short Cycling — Why your AC turns on and off frequently
- AC Breaker Keeps Tripping — Electrical troubleshooting for air conditioners
- AC Making Noise — Identify sounds and their causes
- Outside AC Unit Not Running — Condenser unit troubleshooting
- AC Not Removing Humidity — Dehumidification problems
- Condensation on AC Vents — Sweating vent troubleshooting
- AC Drip Pan Overflowing — Drain line and condensate issues
Window & Portable AC Issues:
- Window AC Freezing Up — Ice on evaporator coil causes
- Window AC Leaking Water — Water leak troubleshooting
- How to Drain a Portable AC — Portable AC maintenance
- Recharging Window AC — Refrigerant considerations
Furnace & Heating Problems:
- Furnace Blowing Cold Air — Why your furnace isn't heating
- Cracked Heat Exchanger — Signs, dangers, and what to do
- Thermostat Not Reaching Set Temperature — System capacity issues
Other Equipment:
- Dehumidifier Freezing Up — Ice buildup causes and fixes
HVAC Efficiency Ratings Explained
Understanding efficiency ratings helps you compare equipment and estimate operating costs. We explain what each rating measures, minimum standards, and what numbers to look for.
- SEER Rating Guide — Seasonal Energy Efficiency Ratio for air conditioners
- EER Rating Explained — Energy Efficiency Ratio and when it matters
- AFUE Rating Guide — Annual Fuel Utilization Efficiency for furnaces
- HSPF Rating Explained — Heating Seasonal Performance Factor for heat pumps
- COP (Coefficient of Performance) — Heat pump efficiency at specific conditions
- CADR Rating Guide — Clean Air Delivery Rate for air purifiers
- BTU vs SACC vs ASHRAE — Portable AC rating standards explained
HVAC Installation Guides
Guides covering proper installation practices, placement considerations, and setup requirements.
- Window AC Installation Guide — Step-by-step installation instructions
- Venting Portable AC Without Window — Alternative venting options
- Bathroom Fan Venting Guide — Proper exhaust fan venting methods
- Thermostat Wiring Guide — Understanding thermostat wire colors
- Cold Air Return Vents — Return air vent placement and sizing
- Ceiling Fan Direction — Summer vs winter rotation settings
- Ceiling Fan Downrod Length — Choosing the right downrod
- Where to Place Air Purifier — Optimal air purifier positioning
- Where to Put a Humidifier — Best humidifier placement
Energy Costs & Comparisons
Tools and guides for understanding, comparing, and reducing HVAC energy costs.
- Gas vs Electric Heating — Cost and efficiency comparison
- Average Electricity Usage — Typical home energy consumption data
- Heating Cost Calculator — Compare costs across heating fuels
- Heat Pump Efficiency vs Temperature — How outdoor temperature affects COP
Indoor Climate & Air Quality
Guides on temperature, humidity, and air quality management for healthy indoor environments.
- Ideal AC Temperature Settings — Recommended thermostat settings
- Indoor Humidity Guide — Optimal humidity levels by season
- Basement Dehumidifier Settings — Humidity control for basements
- Does AC Remove Humidity? — How air conditioners dehumidify
- Dew Point Calculator — Calculate condensation risk
- AC Vent Temperature — Normal supply air temperatures
- How Long to Cool a House — Expected cooling times
- MERV Rating Chart — Air filter efficiency ratings
- Furnace Filter Guide — Choosing the right filter
- HEPA Filter Guide — Understanding HEPA filtration
Insulation & R-Value Guides
Understanding insulation is critical for HVAC efficiency. These guides cover R-values, insulation types, and recommendations by climate zone.
- What is R-Value? — Understanding thermal resistance
- Insulation R-Value Chart — R-values by insulation type
Refrigerant Data & Charts
Technical reference data for HVAC technicians and anyone wanting to understand how refrigerant systems work.
- Refrigerant PT Charts — Pressure-temperature charts for common refrigerants
- Refrigerant Types — R-22, R-410A, R-32, R-454B compared
- Superheat and Subcooling — Measuring and adjusting refrigerant charge
- AC Refrigerant Charge — Signs of low or high charge
Water Heater Guides
Sizing guides and comparisons for tank and tankless water heaters.
- Water Heater Sizing Calculator — Size by First Hour Rating
- Tankless Water Heater Sizing — GPM and BTU requirements
- Tankless vs Tank Water Heaters — Comparison guide
- Hot Water Recirculation Pumps — Types and installation
Equipment Lifespan & Maintenance
Information about HVAC equipment longevity, replacement costs, and maintenance.
- How Long Do AC Units Last? — Expected lifespan by equipment type
- AC Compressor Replacement Cost — Repair vs replace analysis
- Heat Pump Temperature Range — Operating limits for heat pumps
Why We Built HVAC Solver
We built HVAC Solver because we believe you shouldn't need to hire an engineer to understand your HVAC system.
Too many HVAC websites are thinly disguised product review sites or contractor lead-generation tools. They give you vague advice designed to make you call someone—not to actually help you understand your system.
We take a different approach. We publish the same engineering data that HVAC professionals use: load calculations, efficiency ratings, refrigerant charts, diagnostic procedures. If a contractor can look it up, so can you.
What Makes HVAC Solver Different
Engineering Standards
Our calculators use ASHRAE Manual J methodology, ACCA Manual D for duct sizing, and DOE test procedures for efficiency ratings. Not rules of thumb or contractor guesses.
Sourced Data
Every reference table, every formula, every efficiency rating links back to its source. You can verify anything we publish.
No Product Recommendations
We don't review products, rank brands, or tell you which AC to buy. We give you the tools to evaluate options yourself.
Free to Use
All calculators and reference data are completely free. Our only income is display advertising, which doesn't influence our content.
Who HVAC Solver Is For
Homeowners
Sizing a new HVAC system, troubleshooting a problem, or trying to understand energy bills. Our calculators help you have informed conversations with contractors instead of just trusting their recommendations.
HVAC Technicians
Quick reference data in the field. Refrigerant PT charts, superheat and subcooling targets, wire sizing tables—the technical data you need without digging through manuals.
Anyone Curious
If you want to understand how heating and cooling systems actually work, based on physics and engineering rather than marketing, this site is for you.
A Note on Accuracy
Our calculators provide estimates based on industry-standard methodology. They're useful for planning, comparison, and understanding—but they're not a substitute for a professional load calculation performed by a licensed HVAC contractor who can inspect your specific home.
For system sizing and installation, always consult a qualified professional. Our tools help you understand what they're recommending and why.
Get in Touch
Have questions, feedback, or found an error in our data? We'd love to hear from you.
Contact us or email us directly at info@hvacsolver.com
Site Information
- Privacy Policy — How we handle your data
- Terms of Use — Guidelines for using our calculators and content