diff --git a/src/lib/SiteTypes/src/sitetypes/electron.jl b/src/lib/SiteTypes/src/sitetypes/electron.jl
index d8fd90848e..b40f13dfb0 100644
--- a/src/lib/SiteTypes/src/sitetypes/electron.jl
+++ b/src/lib/SiteTypes/src/sitetypes/electron.jl
@@ -27,6 +27,9 @@ function space(
   if !isnothing(conserve_parity)
     conserve_nfparity = conserve_parity
   end
+  if conserve_nf && conserve_nfparity
+    @warn "Setting conserve_nfparity=true when conserve_nf=true for \"Electron\" SiteType will have no effect, and only the \"Nf\" quantum number will be explicitly conserved."
+  end
   if conserve_sz && conserve_nf
     return [
       QN((qnname_nf, 0, -1), (qnname_sz, 0)) => 1
diff --git a/src/lib/SiteTypes/src/sitetypes/fermion.jl b/src/lib/SiteTypes/src/sitetypes/fermion.jl
index 008bdf0877..58e5503181 100644
--- a/src/lib/SiteTypes/src/sitetypes/fermion.jl
+++ b/src/lib/SiteTypes/src/sitetypes/fermion.jl
@@ -28,6 +28,9 @@ function space(
   if !isnothing(conserve_parity)
     conserve_nfparity = conserve_parity
   end
+  if conserve_nf && conserve_nfparity
+    @warn "Setting conserve_nfparity=true when conserve_nf=true for \"Fermion\" SiteType will have no effect, and only the \"Nf\" quantum number will be explicitly conserved."
+  end
   if conserve_sz == true
     conserve_sz = "Up"
   end