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Most contractors know about Manual S. Few really use it.

In this episode of The Heat Pump Podcast, Amply co-founder Eric Fitz walks through Manual S in plain English—breaking down what matters, what doesn’t, and how to design heat pump systems that actually deliver comfort all year long.

Using his own home in Portland, Maine as a case study, Eric explains how to interpret extended performance tables, avoid oversizing, and balance real-world tradeoffs like auxiliary heat and low load cycling. The episode also introduces Amply’s free Manual S spreadsheet tool—designed to take the math and guesswork out of equipment selection.

This is a must-listen for anyone who wants to size systems with confidence, especially in cold climates where comfort and efficiency are harder to get right.

Key Learnings:

• Manual S made simple: Four ratios are all you need Eric walks through them step by step.
• Low-load cycling is real: Why oversizing hurts comfort and efficiency.
• Forget label tonnage: It’s all about the actual performance curves.
• Cold-climate trade-offs: How to balance auxiliary heat and seasonal loads.
• New free tool: Amply’s spreadsheet automates the math – grab it here.
• Local expertise wins: Knowing your regional climate and electricity rates gives you a major edge.

Timestamps

[00:00] - Intro & Free Manual S spreadsheet

[01:35] - Meet Eric Fitz & today’s goal: demystify Manual S

[03:48] - What makes heat pump design so hard (and fun!)

[07:00] - Why your Manual J must be aggressive

[10:15] - Comfort first, efficiency second

[20:00] - The 4 Manual S ratios (and how to use them)

[28:15] - Getting the right performance data

[36:00] - Real-world trade-offs: auxiliary heat, cycling, efficiency

[44:30] - Kilowatt hours vs. energy costs: What matters to homeowners

[52:00] - Wrap-up: tools, tradeoffs, and where to go from here

Resources for Smarter Heat Pump Design: 

• NEEP database: https://ashp.neep.org/#!/
• Amply Manual S tool: https://info.amply.energy/heat-pump-manual-s-free-tool
• ACCA Manual S: https://www.acca.org/standards/technical-manuals/manual-s

Follow the Hosts:

• Ed Smith: https://www.linkedin.com/in/ed-smith-5aa8716
• Eric Fitz: https://www.linkedin.com/in/ehfitz/
• Amply Energy Website: https://www.amply.energy/
• Amply Energy YouTube: https://www.youtube.com/@amplyenergy
• Amply Energy Facebook: https://www.facebook.com/amplyenergy
• Amply Energy Instagram: https://www.instagram.com/amply_energy/