Heat Load Calculator for House

Heat Load Formula:

\[ \text{Load} = \sum (U \times A \times \Delta T) + \text{Gains} \]

U Value:

W/m²K

Surface Area:

m²

Temperature Difference:

Heat Gains:

Heat Load (W):

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1. What is a Heat Load Calculator for House?

Definition: This calculator estimates the heat load required to maintain comfortable temperatures in a house based on building envelope properties and temperature differences.

Purpose: It helps HVAC professionals and homeowners determine the heating requirements for residential spaces.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ \text{Load} = \sum (U \times A \times \Delta T) + \text{Gains} \]

Where:

\( \text{Load} \) — Total heat load (Watts)
\( U \) — U-value of building elements (W/m²K)
\( A \) — Surface area of building elements (m²)
\( \Delta T \) — Temperature difference between inside and outside (Kelvin)
\( \text{Gains} \) — Internal heat gains from appliances, people, etc. (Watts)

Explanation: The formula calculates heat loss through building elements and adds any internal heat gains.

3. Importance of Heat Load Calculation

Details: Proper heat load estimation ensures correctly sized heating systems, energy efficiency, and comfortable indoor environments.

4. Using the Calculator

Tips: Enter the U-value (thermal transmittance), surface area, temperature difference, and any heat gains. For multiple surfaces, calculate each separately and sum the results.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical U-value for walls?
A: Modern insulated walls typically have U-values between 0.1-0.3 W/m²K, while older walls may be 1.0-2.0 W/m²K.

Q2: How do I determine temperature difference?
A: Subtract the outdoor design temperature from your desired indoor temperature (e.g., 20°C inside - (-5°C outside) = 25K difference).

Q3: What are typical heat gains?
A: A person generates about 100W, appliances vary (fridge 100W, TV 200W, etc.), and solar gains depend on window size/orientation.

Q4: Should I include ventilation losses?
A: Yes, for complete calculations add ventilation losses (0.33 × air changes × volume × ΔT).

Q5: How accurate is this calculator?
A: It provides basic estimates. Professional calculations consider more factors like thermal bridging, orientation, and air infiltration.